Do not allow non-system apps to provide unverified attributions am: ec8a2057

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/31451895



Change-Id: I2beea40cab48dcfba1e76b2342290b397e7f5bbf
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>