WP Stories integration - implement StoryNotificationTrackerProvider interface

[mzorz]

This PR builds on top of #12059

This PR implements the new StoryNotificationTrackerProvider interface, which allows the host app to be signaled of when a Notification is being produced by the StorySaveService in the Stories library. Then, it can properly channel the event through to its own SystemNotificationsTracker.

Also in this PR we're checking ARG_NOTIFICATION_TYPE for when an error notification is tapped and properly tracking it down in StoryComposerActivity (see onCreate() in that class).

To test:

1. inject an error when saving an image in PhotoEditor (for example introduce a line that throws an Exception in saveImageFromPhotoEditorViewAsLoopFrameFile().
2. run the WP app, create a new story with an image background frame and tap PUBLISH
3. observe the error notification is shown, and also the trackShownNotification method implemented in the WordPress class is executed. (placing a breakpoint there should be enough).
4. Finally, tap on the error notification and verify the trackTappedNotification method is executed as well.

PR submission checklist:

• I have considered adding unit tests where possible.
• I have considered adding accessibility improvements for my changes.
• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

[peril-wordpress-mobile]

You can trigger optional UI/connected tests for these changes by visiting CircleCI here.

[peril-wordpress-mobile]

You can test the changes on this Pull Request by downloading the APK here.

[jd-alexander]

Hey @mzorz what do you think about putting this class into another file? Just checking because this class is getting a bit big. Let me know though because it's also a really small class 🙏

[jd-alexander]

Thanks for these changes @mzorz I followed the testing instructions and I achieved the expected outcome. I really like this implementation 😉 LGTM 🚢