Crash on startup when running on Android TV emulator

[dturner]

When running UAMP on the Android TV emulator it crashes on startup with the following error:

    --------- beginning of system
2021-09-30 21:05:17.076 1355-1871/? E/ActivityThread: Failed to find provider info for com.google.android.tvsetup.app.machine.services.castsetup.castsetupinfo.CastInfoProvider
2021-09-30 21:05:17.076 1355-1871/? E/CastCPAdapter: Cursor is not valid to read the content provider.
2021-09-30 21:05:17.076 1355-1871/? W/LoadCastServiceInfoTask: Failed to get cast id and certificate from Content Provider.
2021-09-30 21:05:18.079 1355-1871/? E/LoadCastServiceInfoTask: unable to connect to cast service

This is almost certainly because of the dependency on Cast. The code should be updated to only include the Cast dependency on platforms which support Cast i.e. mobile.