Mock Wifi: Added MockWifiServiceUtil in WifiInjector am: 4166e289be am: dab293cfd8 am: 005f6f5d27

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Wifi/+/2845518

Change-Id: I4b9fcbc9e161ca827bf8dfa6b81e74bd0d8a5c3b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>