Avoid fullscreen bounds check while exiting pip

Temporarily remove the check for fullscreen end bounds
while exiting pip in PipTransition, and always set
the bounds to be inherited from parent bounds.

This helps avoid getting stuck in an inconsistent state
while exiting pip via clicking app icon.

The flicker still appears, however, and will have to be fixed
in a later release by running auto-enter-pip in a single transition.

Bug: 286346098
Test: Repeat enter auto-pip and exit by launching from icon
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:96712e6b3abff915831311244a20777036820f4e)
Merged-In: Ie5d5fb1b1249a16ec20d05b2eec4590869251277
Change-Id: Ie5d5fb1b1249a16ec20d05b2eec4590869251277