Tweak new rotate icon and motion

Slightly reduce the icon size to decrease its size relative to the new
back button. Use scaleX attribute to ensure arrows always point in
direction of motion. Fix intro animation bug where rippling would only
happen for first three loops.

Bug: 79930974
Test: manual
Change-Id: I6b8d4acd4c1537649d0120663169e7a1fd4db7fb