Don't commit invisible on a collecting transient-launch task

The visibleAtTransitionEnd mechanism can't be used for
transient-launch; however, we need to avoid the same problem
that it prevents (premutarely committing invisible on a
window that was not hidden by the current transition but
instead a later one).

This CL adds a heuristic for the transient-launch case that
serves a similar purpose.

Bug: 280907903
Test: inject a sleep during finish to ensure that you can
      launch an app before finishing swipe-to-home. Then
      swipe to home and open another app immediately.
Change-Id: I8b3374040c60068d08905b5d2c604b7c250afccf