Centralize assignment of pip enter animation type

In PipTransition, the places to check enter animation type
may have different orders with different scenarios.

Assume swiping a fullscreen landscape app which can enter PiP
to portrait home:

Api request on foreground:
  augmentRequest -> startEnterAnimation -> handleRotateDisplay
Api request on going to background:
  startEnterAnimation -> handleRotateDisplay

Swipe to home:
 Auto-pip:
  augmentRequest -> handleRotateDisplay -> startEnterAnimation
 No auto-pip:
  handleRotateDisplay -> startEnterAnimation

To reduce the complexity of animation type management, assign
the type at entry of entering pip: PipTaskOrganizer#onTaskAppeared
Then PipTransition only needs to read it.

Note that for swiping auto-pip, the type is always ignored
because the animation is done by recents animation.

Bug: 276438425
Test: Swipe a landscape app into pip in portrait without auto-pip.
      The PiP should fade in after the swipe animation.

Change-Id: I98e459fb9913d713cd3b8d44dbb691af61862c56