Merge "Return false when tetherOffloadRuleAdd doesn't really add items" into main am: c694c351c0 am: 12f6e5c8e7

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/3252331

Change-Id: I1898d701be63fede716728735acf9f0c5d1d4d62
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>