Prevent showing windows while animating to avoid color mode switch

If we switch the color mode during a transition, it's pretty much
guaranteed that SF is going to jank. To work around that, we
disallow showing the real content while an activity with a
non-standard-color mode is animating.

Test: Reopen photos, observe no jank
Bug: 79878256
Change-Id: Id27db483844d9424ccfb9afdebd31325eae0cdd8