Merge "Adding Tethering proto" am: 075dd6f8ff

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/2024488

Change-Id: Ie7951e4492ea0dad6aa64218801915643e9d9d7a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>