Fix swipe-PiP-to-home transition with flipv2

Since the new seamless flipv2 is now being used by
config-at-end transitions, we have to adapt the animation
to it as well. Here, I reuse the enter animator to cache
the transforms for activity and task leashes and apply them
with the fraction=1.0.

Bug: 371249390
Flag: com.android.wm.shell.enable_pip2
Test: swipe-up to enter PiP from landscape to portrait
Change-Id: I2e3567a4730984187728d62be77491dbb3b3d120