Merge "Wait for MediaStore idle state to reduce the test flake am: 51fd45cd am: 36f4df55" into tm-d1-dev-plus-aosp am: ad51cda2 am: 27784844

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/DocumentsUI/+/18796607



Change-Id: I788fe52f15634bb3ed095f1cc67e81edd422296a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>