Hide Clear all button during quick switch

- Add support for mMinScrollX to PagedView
- Add RECENTS_CLEAR_ALL_BUTTON as a state-specified visible element
- In BackgroundAppState, set Clear all invisible and bound RecentsView
  scroll to the last task

Test:
- Open an app, quick switch until reaching the end, ensure Clear all
  does not show up and an overscroll effect is performed
- Enter overview, scroll to the end and ensure Clear all shows up
- Same tests in RTL and 3rd party launcher

Bug: 130160876
Change-Id: I5fb958744d0055b83ced1f8b0d7face0e06a0cc5