[automerger skipped] Add android:exported tag am: 2fe8554eae -s ours am: 6d9b730332 -s ours am: 6a26aec165 -s ours am: 96547f6d9f -s ours

am skip reason: Merged-In Icf7492e392cf20986990be2752e6357d4cdb352c with SHA-1 c61b39439e is already in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/developers/samples/android/+/15828964

Change-Id: I3f7295e027d903351d2a0fc4760e11279bffb018