Exclude pip change from separated display change for mixed case

DefaultTransitionHandler only needs to animate the change of display.
It also avoid the default handler from releasing the pip leash that
may be used by pip handler later.

Bug: 429267767
Flag: EXEMPT bugfix
Test: With pip1, swipe to enter pip with changing display
      rotation at the same time.
Change-Id: Ia6d1434cabf2e3e934f6876a0e42052737c2ee48