Prevent unnecessary reordering of the home stack

- Just cancel the recents animation in-place when handling the home button
  to prevent it from being repositioned to the bottom (which stops home)
  and then starting it again (which restarts it)

Bug: 74405472
Test: Press home from an app, ensure launcher stop is only called once
Change-Id: Id41aa2f77c01767cc2c35445458b8f2db81200fc