Fix issue with grouped task rects being calculated slightly off

- This was causing bleed through between split tasks and perhaps
  some rounded corners to be calculated incorrectly
- Also reset the translation after it is adjusted for dismissing
  in case the dismiss gesture is canceled.  This doesn't fix the
  issue with bleed through between the task views (to be fixed
  separately), but makes sure it isn't permanently set on the task

Bug: 206739664
Test: Split tasks, swipe up and check the bounds

Change-Id: I34430e958ca7a75f48621bc27a281e93fdf97179