Fix screenshot/clipboard swipe padding

Ensures that padding is correctly added to screenshot/clipboard UI
to allow dragging the views even when touching slightly outside the
visible area.

Bug: 295373854
Fix: 295373854
Test: manual (visual change): drag the screenshot UI with finger
slightly away from the views (but within 12dp of the edge) and ensure
that the UI is draggable

Change-Id: Ic13acba9c4180771dc0e7879006f39aa7acf6647