Fix tethering unit test fail in R am: 6cee9c5e04 am: 2aa768a7e9

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/14660570

Change-Id: Ie7a89af1a6f7c02cfb79c88248f68ea4bd53e61c