Fix flickering when swiping back to keyguard from hub in landscape

The keyguard elements sometimes flicker when exiting hub in landscape,
if the transition animation starts early, before screen rotation.

The fix is to monitor orientation changes from the Communal Container
and add two flows that derives from the orientation change:
a flow for landscape-to-portrait transition,
a flow for screen rotated to portrait,
to help the Communal Container handle landscape swipe and the Transition
ViewModel control keyguard animation.

Fixes: b/400464568
Test: atest GlanceableHubToLockscreenTransitionViewModelTest
Test: atest CommunalViewModelTest
Flag: com.android.systemui.glanceable_hub_v2
Change-Id: I74c8305131f2a63ba96c132b83884c7057a6f87a