Merge "Move TetherStatsKey and TetherStatsValue to common libs" am: 8315d1cf03

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/2054166

Change-Id: Iff314d5048d718f7e10d8d312aba8f7ad3e1ad6b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>