[quick_actions] Add guidance for correcting task management/back press behavior for apps with launcher activities (flutter#7686)

### What
Adds a note about correcting the task management/back press behavior for apps that use launcher activities to the `README`. Fixes flutter/flutter#152883.

### Why
If apps use a launcher activity, then launching shortcuts created by the plugin may not behave as expected because the plugin expects to launch the main `FlutterActivity`, for which it configures the launch mode, but instead launches the launcher activity, which it does not account for.

To fix this, the launcher activity itself needs to have a launch mode configuration that makes sense for the app. This involves changing the launch mode of the launcher activity in the manifest and/or using the right `Intent` flags to launch the main `FlutterActivity`.

From my work on the issue linked above, I found that if the launcher activity only launches the main `FlutterActivity` without any additional relevant logic, to maintain the exact same behavior of the plugin with/without a launcher activity, the launcher activity can use the `singleInstance` launch mode. So, I included a note about this. However, in more complex launcher activities, like b/357028168 that inspired the original issue, other modes may need to be used.

Author: camsim99

packages/quick_actions/quick_actions/CHANGELOG.md

@@ -1,6 +1,7 @@
-## NEXT
+## 1.0.8
 
 * Updates minimum supported SDK version to Flutter 3.19/Dart 3.3.
+* Adds reference to `quick_actions_android` README in the Android section of the README.
 
 ## 1.0.7
 

packages/quick_actions/quick_actions/README.md

@@ -52,3 +52,6 @@ If the drawables used as icons are not referenced other than in your Dart code,
 you may need to
 [explicitly mark them to be kept](https://developer.android.com/studio/build/shrink-code#keep-resources)
 to ensure that they will be available for use in release builds.
+
+For more information on using this package on Android, see the
+[`quick_actions_android` README](https://github.com/flutter/packages/blob/main/packages/quick_actions/quick_actions_android/README.md).

packages/quick_actions/quick_actions/pubspec.yaml

@@ -3,7 +3,7 @@ description: Flutter plugin for creating shortcuts on home screen, also known as
   Quick Actions on iOS and App Shortcuts on Android.
 repository: https://github.com/flutter/packages/tree/main/packages/quick_actions/quick_actions
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+quick_actions%22
-version: 1.0.7
+version: 1.0.8
 
 environment:
   sdk: ^3.3.0

packages/quick_actions/quick_actions_android/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 1.0.16
+
+* Updates README to include guidance on using the plugin with a launcher activity.
+
 ## 1.0.15
 
 * Updates lint checks to ignore NewerVersionAvailable.

packages/quick_actions/quick_actions_android/README.md

@@ -11,10 +11,35 @@ so you do not need to add it to your `pubspec.yaml`.
 However, if you `import` this package to use any of its APIs directly, you
 should add it to your `pubspec.yaml` as usual.
 
+## Usage with launcher activities
+
+If your app implements an activity that launches the main `FlutterActivity`
+(`MainActivity.java`/`MainActivity.kt` by default), then you may need to change
+the launch mode of your launcher activity and/or modify the `Intent` flags used
+to launch the main `FlutterActivity` in order to achieve the desired back press
+behavior and task management.
+
+If your launcher activity only launches the main `FlutterActivity` without any
+additional relevant logic (like the code sample provided in the description of
+https://github.com/flutter/flutter/issues/152883), to have your app maintain the
+same behavior of `quick_actions_android` with/without a launcher activity, set
+the launch mode of your launcher activity to `singleInstance` in
+`your_app/android/app/src/mainAndroidManifest.xml`:
+
+```xml
+<activity
+        ...
+        android:launchMode="singleInstance">
+```
+
+See the [Tasks and the back stack][4] Android documentation for more information
+on the different launch modes and `Intent` flags you may need.
+
 ## Contributing
 
 If you would like to contribute to the plugin, check out our [contribution guide][3].
 
 [1]: https://pub.dev/packages/quick_actions
 [2]: https://flutter.dev/to/endorsed-federated-plugin
 [3]: https://github.com/flutter/packages/blob/main/CONTRIBUTING.md
+[4]: https://developer.android.com/guide/components/activities/tasks-and-back-stack#TaskLaunchModes

packages/quick_actions/quick_actions_android/pubspec.yaml

@@ -2,7 +2,7 @@ name: quick_actions_android
 description: An implementation for the Android platform of the Flutter `quick_actions` plugin.
 repository: https://github.com/flutter/packages/tree/main/packages/quick_actions/quick_actions_android
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+in_app_purchase%22
-version: 1.0.15
+version: 1.0.16
 
 environment:
   sdk: ^3.4.0