Make PipTransition use animators bounds for unhandled case

PipTransition is the last one to handle the rotation. It is first
going through PipController.mRotationController, which sets the bounds
to value A, then PipKeepClearAlgorithm updates those to B due to IME
or shelf height adjustments, and finally PipTransition performs an
unhandled PiP transition, but still uses the bounds from A, which are
missing the keep clear area adjustment.

The events are disjoint and we shouldn't rely on their ordering, hence
keep clear area change should keep triggering animation.

There is still a small flicker visible if the distance to travel by PiP
is large (like with IME), because at that point the PipTransition
callback comes before the animator finishes, thus putting it in the
final position before the animators end through the finishTransaction.

Bug: 285242520
Test: before http://recall/-/ekEuGtt9d9HWqkUtAzpHx8/cLtiXGYUyItm2kNCCEkkWA
Test: after http://recall/-/ekEuGtt9d9HWqkUtAzpHx8/iPs6fwdSXG3TE0IERmxA8
Change-Id: I713a02ae90c8bdd6ff11e43a5c4f9ff959d2342e