Fix bubble expanded view jumping to the left when switching bubbles

When the bubbles are shown vertically on the left side of the screen
and you tapped between them, the view would be misaligned for a bit
during the animation.

This was happening because the padding being applied to the view
didn't account for the space the pointer triangle took up.

The fix is to add the size of the pointer to the padding when
showing vertically on the left side.

Bug: 196444014
Test: manual - expand a bubble on a large screen on the left side
             - tap between the bubble and the overflow or other
               bubbles
            => observe that the expanded view doesn't jump a bit to
               the left
      manual - test switching between bubbles on phone, phone
               landscape (left & right sides), and tablet on the
               right side
            => observe that the animation looks correct
Change-Id: Icb3cd87843504ab31da8005fb72f36daae387d39