Update layer of rotation leash when restoring pip to original task

This is similar to I6172e69400a258d9fdbc66044b459d65af622d14
Just the original task contains more than 1 activity.
E.g. after reparenting:
layer=0 activityZ=0
layer=1 activityZ=1
layer=2 activityZ=2 <- pip
But if the pip has a rotation leash, its layer is not synced
with activityZ, then it becomes layer=2 leashZ=0{activityZ=2}.
That causes the top activity becomes invisible awhile before
the leash is removed.

Bug: 369006473
Flag: EXEMPT bugfix
Test: Expand a pip which will reparent to a top task with
      2 activities with orientation change.
      The previous fullscreen activity should not flicker on top.
Change-Id: I2810646bb9b1be1782dcb5ec06d86d21125778c4