Cancel pending animation when state changed.

The participants of pending animation were cached while another
transition playing, so when a transition finish, the participant target
could already changed or removed. We can use NavigationMonitor to
cancel the pending animation if the target has changed.

Bug: 277663454
Test: manual, try to verify the pending animation shouldn't start when
navigation window has changed.

Change-Id: I4db578bd46932549afe5f3cb7f2e0f147bbf1a82