[ADI][metrics] log UID of installed app

This is added so that we know what has been installed or updated with
what verification policy and result.

+ some code clean up for better manual logging testing

FLAG: android.content.pm.verification_service
BUG: 418283971
Test: statsd_testdrive 1101

Change-Id: I3bf40bd4332635e9a5c391f805a40b1de8776715