Ensure home control dream is enabled in user context

Currently we use the system user's PackageManager to enable/disable the
home controls dream. This change ensures we always use the current
user's package manager instead.

Bug: 370691405
Test: HomeControlsDreamStartableTest
Flag: com.android.systemui.home_controls_dream_hsum
Change-Id: I8768b091a8e53324883afcf16c4f0ede65ffd11c