Merge "Only send to downstream ifaces for null network" am: 5a1c614e42

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/2598346

Change-Id: I30cd4a5fc97652c383dd0deea22a99f35f0f4db6
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>