Add logs for group child notification removal animation start and end am: 58ee34ab am: f30c7251

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23768304



Change-Id: Ifd77c2e30672b682683a25d0217c42ab79e7a281
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>