Transitions can also be aborted after start.

They only stop being abortable once they are playing.
START is valid.

Auto's tests seem to hit this case frequently when it
kills/restarts their carlauncher.

Bug: 255631687
Test: test_mapping_presubmit_cloud_auto_car_services
Change-Id: I8564e5dfef541fa06717ebbd77ae4e03016b6906