Fix thresholds with deferred-start swipe up gestures

- We were previously using the drag threshold (10dp) for both gesture start
  and drag start, when we should be using the touch threshold (24dp) for
  the deferred gesture start to ensure it coincides with the touch threshold
  for the buttons in the nav bar.

Bug: 79970627
Test: Swipe up over the back button, ensure that we don't both start the
      animation and also trigger back press

Change-Id: Ib4b2a3e2492da144485f87be5477eabf3e96e843