Fix bug with home panel dream

This change adds a new flow to AuthorizedPanelsRepository to listen to
changes in the set of authorized panels. We then subscribe to this flow
in the home panel dream interactor to ensure that we properly disable
the dream if the list of authorized panels changes.

This change also cleans up some tests/fakes in favor of using the real
implementation of the repositories (and just faking the shared
preferences inputs).

Fixes: 323077279
Test: verified that removing authorized apps will now disable the dream
Test: atest SystemUITests
Flag: ACONFIG android.service.controls.flags.home_panel_dream STAGING
Change-Id: I1f553bd4d29f8c373a0fb1766869aa86f955171f