Unfreeze the surface when the transition is done

The surface was not unfreeze if the WindowContainer is closing and
changing after [1].

Always check and unfreeze the surface if needed when the transition
is done.

[1] d19ad2aa

Bug: 280754787
Test: click web link on chat while having a Meet call
Change-Id: I98618477a828eb72b2173af6988e804471139e81