Reuse SwipeAnimation in PredictiveBackHandler

This CL makes PredictiveBackHandler reuse SwipeAnimation instead of
implementing its own transition. This makes the back transition work out
of the box with overlays.

Because PredictiveBackHandler used to handle previews but SwipeAnimation
didn't, the preview animation logic from PredictiveBackHandler was moved
to SwipeAnimation, making previews now work with all swipe transitions.

Bug: 353679003
Test: PredictiveBackHandlerTest
Test: OverlayTest
Flag: com.android.systemui.scene_container
Change-Id: Ibef4b8f2a1a2658e8028c41149852b88440e0da0