Ship the onboarding widget prompt and remove the Add to Dock experiment (#9857)

Task/Issue URL:
https://app.asana.com/1/137249556945/project/72649045549333/task/1217068101576174
Tech Design URL (if applicable): 
API Proposals URL(s) (if applicable): None

### Description
The `onboardingPrompts` / `addToDockAndWidgetExperimentJul25` experiment
concluded with the widget-only variant winning. This PR ships that
variant and cleans up the experiment:

- The widget prompt (`widget_prompt` + `add_widget` steps, right after
the default browser prompt) is now a default step of the linear
onboarding plan for every user without an installed widget, reinstallers
included.
- Removed `OnboardingPromptsExperimentManager`,
`OnboardingPromptsToggles` and `OnboardingPromptsExperimentMetrics`,
along with the metric calls in `WidgetAddedReceiver`,
`SystemSearchViewModel` and `OnboardingCompletedMetricObserver`, and the
prerequisite check in `SegmentedOnboardingExperimentManager`. The
`onboardingPrompts` feature is also removed from the bundled
`privacy_config.json`.
- Removed everything Add to Dock related: step, dialog, step id, dialog
type, `onboarding_add-to-dock` pixel, both welcome-page branches, the
config-driven resolver/binder/controller entries, the tutorial video,
sketch-frame drawable, include layout, `AspectRatioTextureView`, dimen,
lint-baseline entry, and the English and translated strings (lint-vital
fails release builds on `ExtraTranslation` otherwise).
- Maestro: the widget prompt is now a mandatory step in
`pre_onboarding.yaml`; the `linearWidgetPromptShown` output flag is gone
and `onboarding_dismiss_all_dialogs.yaml` asserts the in-context widget
CTA is not shown.

### Steps to test this PR

_Fresh install, no widget_
- [x] Install a fresh build and go through onboarding
- [x] After the default browser prompt, verify the "Try our Home screen
widget" page shows with a step indicator
- [x] Tap "Add widget" and verify the system pin dialog appears, then
the flow continues to the address bar position page
- [x] Complete onboarding, open a New Tab Page and verify the widget
bottom sheet is NOT shown

_Fresh install, skip widget_
- [x] Go through onboarding and tap "Not Now" on the widget page
- [x] Verify the flow continues to the address bar position page and the
widget bottom sheet is NOT shown afterwards

_Widget already installed_
- [x] Add a DuckDuckGo widget to the home screen before the widget page
is reached and verify the widget page is skipped

_Reinstall_
- [x] Install the app as a reinstallers, choose to go through full
onboarding, and verify the widget page is shown

_Add to Dock_
- [x] Verify no "Add me to your favorites row" page appears anywhere in
onboarding

_Automated_
- [ ] Maestro `onboarding/onboarding.yaml` and
`onboarding/onboarding_dismiss_all_dialogs.yaml` pass

### UI changes
| Before  | After |
| ------ | ----- |
Widget prompt only for the `treatmentWidgetOnly` /
`treatmentDockAndWidget` cohorts; Add to Dock page for dock
cohorts|Widget prompt for everyone without a widget; no Add to Dock
page|

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>

Author: catalinradoiu

.maestro/onboarding/onboarding_dismiss_all_dialogs.yaml

@@ -52,20 +52,11 @@ tags:
           text: ".*Remember: every time you browse with me a creepy ad loses its.wings..*"
       - runFlow: ../shared/browser_screen/click_on_tabs_button.yaml
       - tapOn: "New Tab"
-      - runFlow:
-          when:
-            true: ${!output.linearWidgetPromptShown}
-          commands:
-            - assertVisible:
-                text: ".*Try our Home screen widget!.*"
-      - runFlow:
-          when:
-            true: ${output.linearWidgetPromptShown}
-          commands:
-            - extendedWaitUntil:
-                visible:
-                  text: ".*Try our Home screen widget!.*"
-                timeout: 3000
-                optional: true
-            - assertNotVisible:
-                text: ".*Try our Home screen widget!.*"
+      # The widget prompt in linear onboarding replaces the in-context widget CTA.
+      - extendedWaitUntil:
+          visible:
+            text: ".*Try our Home screen widget!.*"
+          timeout: 3000
+          optional: true
+      - assertNotVisible:
+          text: ".*Try our Home screen widget!.*"

.maestro/shared/pre_onboarding.yaml

@@ -1,8 +1,5 @@
 appId: com.duckduckgo.mobile.android
 ---
-# Consumers need to know whether the linear widget step was shown: it and the end-of-onboarding widget
-# bottom sheet are mutually exclusive (see AddWidgetModalEvaluator).
-- evalScript: ${output.linearWidgetPromptShown = false}
 - assertVisible:
     text: ".*(Ready for a faster browser that protects you and lets you decide when and how to use.AI|Ready for a faster browser that puts you in.control).*"
 - tapOn:
@@ -29,32 +26,9 @@ appId: com.duckduckgo.mobile.android
       true: ${SET_AS_DEFAULT != 'true'}
     commands:
       - tapOn: "cancel"
-# The "Add to Dock" / "Widget prompt" onboarding pages only show for some cohorts of the
-# addToDockAndWidgetExperimentJul25 experiment (see OnboardingPromptsToggles); both are optional so
-# this flow stays deterministic regardless of which cohort a run gets enrolled into.
-- extendedWaitUntil:
-    visible:
-      id: "addToDockTitle"
-    timeout: 3000
-    optional: true
-- runFlow:
-    when:
-      visible:
-        id: "addToDockTitle"
-    commands:
-      - tapOn: "Got it!"
-- extendedWaitUntil:
-    visible:
-      id: "widgetPromptTitle"
-    timeout: 3000
-    optional: true
-- runFlow:
-    when:
-      visible:
-        id: "widgetPromptTitle"
-    commands:
-      - tapOn: "Not Now"
-      - evalScript: ${output.linearWidgetPromptShown = true}
+- assertVisible:
+    id: "widgetPromptTitle"
+- tapOn: "Not Now"
 - assertVisible:
     text: ".*where should I put your address.bar?.*"
 - tapOn: "next"

PixelDefinitions/pixels/definitions/onboarding.json5

@@ -132,21 +132,6 @@
             }
         ]
     },
-    "onboarding_add-to-dock": {
-        "description": "Add-to-Dock onboarding page. shown when the page is displayed; clicked when the user taps Continue. Unique once per user per event.",
-        "owners": ["catalinradoiu"],
-        "triggers": ["other"],
-        "suffixes": ["form_factor"],
-        "parameters": [
-            "appVersion",
-            "onboardingEvent",
-            "onboardingInstallType",
-            "onboardingDaysSinceInstall",
-            "onboardingFlow",
-            "onboardingPixelSource",
-            { "key": "value", "type": "string", "description": "Only set when event=clicked.", "enum": ["engage"] }
-        ]
-    },
     "onboarding_widget-prompt": {
         "description": "Widget-prompt onboarding page. shown when the page is displayed; clicked engage/dismiss on the Add widget / Skip CTAs; confirmed added/not_added after the system add-widget prompt returns. Unique once per user per (event, value).",
         "owners": ["catalinradoiu"],

app/lint-baseline.xml

@@ -5709,17 +5709,6 @@
             column="20"/>
     </issue>
 
-    <issue
-        id="VectorRaster"
-        message="Limit vector icons sizes to 200×200 to keep icon drawing fast; see https://developer.android.com/studio/write/vector-asset-studio#when for more"
-        errorLine1="    android:width=&quot;281dp&quot;"
-        errorLine2="                   ~~~~~">
-        <location
-            file="src/main/res/drawable/onboarding_add_to_dock_sketch_frame.xml"
-            line="2"
-            column="20"/>
-    </issue>
-
     <issue
         id="VectorRaster"
         message="Limit vector icons sizes to 200×200 to keep icon drawing fast; see https://developer.android.com/studio/write/vector-asset-studio#when for more"

app/src/main/java/com/duckduckgo/app/onboarding/OnboardingCompletedMetricObserver.kt

@@ -36,7 +36,6 @@ import javax.inject.Inject
 class OnboardingCompletedMetricObserver @Inject constructor(
     @AppCoroutineScope private val appCoroutineScope: CoroutineScope,
     private val userStageStore: UserStageStore,
-    private val onboardingPromptsExperimentMetrics: OnboardingPromptsExperimentMetrics,
     private val segmentedOnboardingExperimentMetrics: SegmentedOnboardingExperimentMetrics,
     private val onboardingPasswordImportExperimentMetrics: OnboardingPasswordImportExperimentMetrics,
 ) : MainProcessLifecycleObserver {
@@ -45,7 +44,6 @@ class OnboardingCompletedMetricObserver @Inject constructor(
         userStageStore.userAppStageFlow()
             .filter { it == AppStage.ESTABLISHED }
             .onEach {
-                onboardingPromptsExperimentMetrics.fireOnboardingCompletedMetric()
                 segmentedOnboardingExperimentMetrics.fireOnboardingCompletedMetric()
                 onboardingPasswordImportExperimentMetrics.fireOnboardingCompletedMetric()
             }

app/src/main/java/com/duckduckgo/app/onboarding/OnboardingPromptsExperimentManager.kt

@@ -42,7 +42,6 @@ class SegmentedOnboardingExperimentManagerImpl @Inject constructor(
     private val onboardingBrandDesignUpdateToggles: OnboardingBrandDesignUpdateToggles,
     private val segmentedOnboardingFeatureToggles: SegmentedOnboardingFeatureToggles,
     private val onboardingPasswordImportToggles: OnboardingPasswordImportToggles,
-    private val onboardingPromptsToggles: OnboardingPromptsToggles,
     private val appBuildConfig: AppBuildConfig,
     private val dispatcherProvider: DispatcherProvider,
     private val onboardingPrivacyConfigPersistedGate: OnboardingPrivacyConfigPersistedGate,
@@ -65,7 +64,6 @@ class SegmentedOnboardingExperimentManagerImpl @Inject constructor(
     private suspend fun checkPrerequisites() =
         onboardingBrandDesignUpdateToggles.brandDesignUpdate().isEnabled() &&
             onboardingBrandDesignUpdateToggles.configDrivenDialogs().isEnabled() &&
-            !onboardingPromptsToggles.addToDockAndWidgetExperimentJul25().isEnabled() &&
             !onboardingPasswordImportToggles.passwordImportExperimentAug25().isEnabled() &&
             !appBuildConfig.isAppReinstall()
 }

app/src/main/java/com/duckduckgo/app/onboarding/OnboardingPromptsExperimentMetrics.kt

@@ -37,7 +37,6 @@ sealed interface NewUserOnboardingActivityDialog {
     data object AiComparisonChart : NewUserOnboardingActivityDialog
     data class SegmentedComparisonChart(val chart: ComparisonChartConfig) : NewUserOnboardingActivityDialog
     data object DefaultBrowserPrompt : NewUserOnboardingActivityDialog
-    data object AddToDock : NewUserOnboardingActivityDialog
     data object WidgetPrompt : NewUserOnboardingActivityDialog
 
     data object AddWidget : NewUserOnboardingActivityDialog