Merge "Add testutil to mock android.app.usage.NetworkStats" into main am: 24b9bd7fa6 am: 59061ebbb6

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/3227682

Change-Id: Ieff8e7f34ad792a0ec3ea811993466be95bd32ef
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>