Merge "UpstreamNetworkMonitor: remove unused mTetheringUpstreamNetwork" am: 42d28f1d66 am: 7fb5392945

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/2383987

Change-Id: If65e321cca36859c17305507469a5151e4b50f86
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>