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: I9a0969bbf226864c1e0cd6480ed7a95b3b785b76
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>