TIS: Singleton TIS for Broadcast Feature Support

Granting TvProvider privapp permission, create getClientUserId API and
change TIS to be a singleton.

Flag: android.media.tv.flags.kids_mode_tvdb_sharing
Bug: b/288383796
Test: manual test on device and verified by vendor.

Change-Id: I3a4cfd408d49ac3183536a859a3b14b13a2b290e