We register TWA client apps to know when we should offer to clear data. When a client app is uninstalled we can safely unregister an app (since the app is no more!).

When a client app has its data cleared, we show a dialog but don't unregister the app, since the user may or may not clear data. This means that if the user clears data for the same app multiple times we'll show the clear data dialog every time.

We should see if the user actually does clear the data, and in that case unregister the app.