End current key button animations when the button is hidden

- If the ripple animation doesn't finish before the view is hidden
  and not scheduled to draw, the render node animation will not
  finish, leaving the ripple visible until it is next touched.
  Instead, we should just end existing animations whenever the
  buttons are made invisible

Bug: 168422286
Test: Extend ripple duration beyond the dismiss nav bar window
      duration and verify bug happens without change and is fixed
      with the change

Change-Id: If3a38bcd47cc7665ee42c66f688cf306c7fab44c