Never set resized while not drag resizing for pinned stack.

It's not necessary in the pinned stack and interferes with the
animation. It's not enough to just check getBoundsAnimating, as
we turn that off prior to the final resize so that we unmute
notifications to the client.

Bug: 28559097
Change-Id: Iae180c8a8ca0585184efcf24e7677557a33678eb