[DataStore] Observe and ObserveQuery do not include nested data for items synced over the network on Android

[Jordan-Nelson]

Describe the bug
The item included in the subscription event from the observe() API does not include nested belongsTo data when the item is synced over the network on Android.

To Reproduce
Steps to reproduce the behavior:

1. Create an app with a belongTo relationship with cloud sync (Blog/Post)
2. Set up an observe subscription on the model with a belongsTo relationship (ex: Post)
3. Run the app on Android and add some data (several Posts)
4. Close the app and clear data (or uninstall)
5. Launch the app again
6. Notice that the create events from observe() do not include nested data
7. Run the test again with iOS, and notice that the create events from observe() do include nested data

Expected behavior
Nested data for belongsTo relationships should be included in the item emitted from Observe()

Platform
Amplify Flutter current supports iOS and Android. This issue is reproducible in (check all that apply):
[x] Android
[] iOS

Additional context
This was already fixed for the Query() API in this PR. A similar change may be needed for Observe().

[Jordan-Nelson]

This needs to be fixed in Amplify-Android. See aws-amplify/amplify-android#1566

[Jordan-Nelson]

The issue was resolved for native apps. It was unfortunately not resolved for flutter apps using amplify-android. See aws-amplify/amplify-android#1610

[Jordan-Nelson]

This was resolved in Amplify Flutter v0.3.2