Remove app access to qtaguid ctrl/stats file

Remove the untrusted apps and priviledged apps from the group that can
directly access xt_qtaguid module related file. All apps that need to
access app network usage data need to use the public API provided in
framework.

Test: Flashed with master branch on marlin, verified phone boot, can
      browse web, watch youtube video, make phone call and use google
      map for navigation with either wifi is on or off.
      run cts -m CtsNetTestCases -t android.net.cts.TrafficStatsTest
      run cts -m CtsNativeNetTestCases
Bug: 68774956 30950746

Change-Id: I9b3db819d6622611d5b512ef821abb4c28d6c9eb