Add getOverviewFullscreenProgress() to LauncherState

- BackgroundAppState sets this to 1, all other states set it to 0
- QuickSwitchState extends BackgroundAppState, and calculations for
  fullscreen scale/translation are moved to BackgroundAppState
- Move fullscreen progress logic out of WindowTransformSwipeHandler
  and into the launcher activity controller, which uses the new
  RecentsView.FULLSCREEN_PROGRESS property to animate it

Bug: 130020567
Change-Id: If6265fcce3749050be354742e7d2c418d11ee9bb