Merge "Fix extra transition animation played after back gesture trigger." into udc-dev am: 58aab277 am: a696e2ac

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/22240772



Change-Id: I25a8d80494ebd61d5d7c80f824f4a49ea97676f9
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>