Dismiss dream on swipe-up gesture

This always uses the bouncerless scrim controller, which will dismiss
the dream - instead of pulling up the bouncer. This ensures that even
for interactive dreams, we can still exit the dream by swiping up.

Flag: android.service.dreams.dreams_v2
Test: atest DreamOverlayServiceTest
Test: atest ScrimManagerTest
Test: manually on interactive dream and swiping up
Fixes: 411408037
Change-Id: I87ea4eb247bf07cb7d3e6407d40ba0868cbed2c4