Allow apply animation to ActivityRecord after transfer starting window.

If there are two activities be start continuous, it might have a chance
that opening transition cannot be applied becuase the starting window
just been transferred to secondary activity.
To fix this, only set mUseTransferredAnimation to true when the first
ActivityRecord is animating.

Bug: 155030898
Test: atest TaskSnapshotControllerTest AppWindowTokenTests
Test: atest AppWindowTokenTests#testTransferStartingWindowCanAnimate
Change-Id: I09166094514a5867e24e8421e0c829dd7446b123