Set windowing mode when exit PIP to fullscreen

Before, we only setActivityWindowingMode when exit PIP. It won't
request display rotation nor update the visibility of other activities
behind, which will result the EXIT_PIP transition won't actually rotate
the display, and will follow by another CHANGE transition for the
rotation.

Bug: 210965919
Test: pass existing
Change-Id: I402449fddc1ddcd4c876489b5fb96a2a599baa1d