Prevent exfiltration of system files via avatar picker. am: f70e351d1a am: 05ea36ddc5 am: ff5b6611cf

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Settings/+/19745058

Change-Id: Id74cd5fe28cec05a3fd87fc5434d28fad639e1b8
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>