Always detach transition-created surfaces on finish

This already happens in the finishTransaction, but we are seeing
some cases of these not being cleaned-up. It's not clear how that
can actually happen besides an animation impl doing the wrong
thing; however, since it seems to happen occasionally, add some
failsafe logic to ensure it is detached.

Bug: 275187029
Test: Existing tests pass since no functional change.
Change-Id: I1622d088a6d326bd1a534f88b40b67491bb13230