Merge "Only send to downstream ifaces for null network" am: 5a1c614e42 am: 34918c033e

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

Change-Id: I5397ed6046bd915725a537f63a6da5a3b9df5a26
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>