Show pip until drawn with entering bounds if rotation changes

The request transition may be a CHANGE type for display rotation,
So augmentRequest is unable to set the entering bounds at the
request stage. And when the CHANGE transition is ready, it includes
the entering pip info. Then the entering bounds will be applied at
the end of enter animation, which could cause to flicker because
the redraw of app configuration. The case only happens with type
ANIM_TYPE_ALPHA (i.e. swipe enter non-auto pip) because there
won't have pip overlay. Note that pip overlay is not a good option
for ANIM_TYPE_ALPHA because the non-opaque alpha is applied on task,
it will be ugly that both overlay and app content are visible.

So just simply keep the pip task invisible until it is redraw with
the entering bounds, and then play fade-in animation when the
drawn transaction is committed.

Bug: 342071665
Test: Swipe entering a non-auto pip activity.
      The pip activity should not flicker during the
      fade-in animation.

Change-Id: Idd6a7f8b70c0e28cc570af77c72f3b9e1a997f72