Merge "TetheringTest: replace upstream change check by event callback" am: 119e5adc14 am: 6bd7513ce6

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/2383985

Change-Id: If4a63dfac9bb51e1c6de7b3176a60e86d115a58f
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>