Do not enter pip during transient launch.

When Pair-to-pair switch, the closing task is accidentally enter pip
during startActivityFromRecents => moveTaskToFront, which cause two
problems:
1. Pip transition should happen after transient launch finich.
2. StageCoordinator cannot handle the pip change, so that pip
   task will enter a strange situation.
By checking whether the current top root task is transient hide, if it
does, don't allow it to enter pip while pausing. And if that task
really need to enter pip, it shall happen after transient launch was
committed.

Bug: 290857445
Test: Do pair-to-pair quick switch with an auto-pip app exist, verify
no auto pip happen like switch on fullscreen app.
Test: Verify swipe up to enter auto-pip still work.

Change-Id: I81b1bbc2e3b8617b64ec92d2ce4a528ebe8aaaa6