Not report DNS failures caused by network restriction errors

Failures caused by network access restrictions account for a large
portion of metrics traffic (~27%). The change stops reporting this type
of errors to cloud.

Bug: 288340533
Test: Manually test
      1. Install a test app that keeps sending DNS in background.
      2. Force enable doze mode by adb commands.
      3. Check that DNS query results of the test app is failed.
      4. Use statsd_testdrive to confirm that query failures are not
         reported to statsd when network for the app is blocked.
Change-Id: I00d9d633e8cff2a75e9d2b6c55562a7cba5f39ad