Add hub -> dreaming transition

Copies much of the logic for lockscreen -> dreaming, considering
AOD/DOZING as invalid from states.

Fixes: 316415264
Test: atest SystemUITests:KeyguardTransitionScenariosTest
Flag: ACONFIG com.android.systemui.communal_hub STAGING
Change-Id: I8ba0d70fb056a1669b56820ed59de9a5f30b7330
2 files changed