Merge "Clarify ResolverActivity inheritance contract." into tm-qpr-dev am: a1355cd0ff am: b66f9f08e0

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/modules/IntentResolver/+/21377183

Change-Id: I1e087acf385c961776777a8d4747e5b9e53f8c58
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>