Merge "Set dialog background activity start mode on U+" am: 7b766a2ff6 am: 20663017b6

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/2528741

Change-Id: I0e63eed72e3035123513d21e775e484aa5230db1
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>