Only play ActivityEmbedding animation if there is AE split

Same as the legacy app transition, we want to play the app customized
animation if there is no AE split.

We don't support app customized animation when there is AE split yet to
make the animation consistant.

Bug: 207070762
Test: atest WMShellUnitTests:ActivityEmbeddingControllerTests
Test: atest WmTests:TransitionTests
Change-Id: I68348cd650b9dbc8c39ef8d22a171d128e196882
6 files changed