Merge "Move TetherStatsKey and TetherStatsValue to common libs" am: 8315d1cf03 am: adc1a7c1fb

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

Change-Id: Ib10df2e5c05344be82653a3a5cfff918792c2c93
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>