Hide non-system overlay window on ActivityPicker am: c4121c15e4

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Settings/+/17628100

Change-Id: I54645a67488b6c155218eca6c5fb5779daabd495
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>