Fix dream overlay lifecycle when bouncer is showing in scene container

The DreamOverlayService observes bouncer showing state to update its
lifecycle so touch monitor is correctly started/stopped. This change
makes it so this state is correctly handled when scene container is
enabled.

Test: atest DreamOverlayServiceTest
Test: touch monitor stopped when bouncer is showing over dream when
      scene container is enabled
Fix: 379179472
Flag: com.android.systemui.scene_container
Change-Id: I3d6271c29db5b8059007b77993fd1b1252691edc