Allow organizer to handle transition for non-embedded activity

We want to allow organizer to handle the transition in case like
launching split TaskFragments from a non-embedded activity.

Bug: 200496784
Test: atest WmTests:AppTransitionControllerTest
Test: test with demo app to launch split from non-embedded
Change-Id: Iaf1d07c8cf43fa773fede3c031855085147be263