Update HomeControlsDreamService to support HSUM

The service will always run in the foreground user, and will no longer
depend on the interactor directly. Instead, it will use a data source -
which will be a remote data source when the flag is enabled.

Bug: 370691405
Test: atest HomeControlsDreamServiceTest
Flag: com.android.systemui.home_controls_dream_hsum
Change-Id: I263379251895e8dacbd668dc4c51d445c9514620