Reland "Support transitioning from doze to dream from button press."

This reverts commit 1c6fa730.

Reason for revert: This change addresses the original null pointer exception

Test: atest DozingToDreamingTransitionViewModelTest
Test: PhoneWindowManagerTests#powerPress_withoutDreamManagerInternal_doesNotCrash
Bug: 389155961
Flag: com.android.systemui.glanceable_hub_v2
Change-Id: I0f27b132bb9368c281e9924d63a045c8ed9663fc