Allow PipTouchHandler to re-enable the touches

This is to fix the regression from ag/21471704 that
PipTouchHandler#setTouchEnabled(true) is not called due to
PipAnimationController#quietCancel when receives display changed
callback, which happens on folding the display.

Bug: 272825196
Test: manual, follow the reproduces in b/272825196
Test: manual, make sure no regression following b/263211281
Change-Id: I3f18680856bd3705af8ca374bf1592ae97499071