Use screen rotation animation only if the display has content

It is unnecessary to run animation which is invisible to user.
Especially when adding a new display which is empty initially.

Also make sure that the leash for fade rotation animation is valid.
(For the case if the animation was canceled by other places.)

Bug: 213562756
Test: Either use legacy transition or shell transition.
      Start ScreenRecord and check logcat that there is no
      "Screen frozen" or "Creating Transition".
Change-Id: I8e905e4161a8eb768eadda4b160af57b7148f81d