Merge "Add SysUI flag notification_clearable_refactor" into udc-qpr-dev am: de88986a

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/24146308



Change-Id: I259e9e57be97cd9aee06b543a653e9e2f2bfff3a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>