Fix the UPDATE_DEVICE_STATS permission for multiuser

When an additional user is using the device, netd should filter out the
userId prefix when checking the UPDATE_DEVICE_STATS permission.

Bug: 111560570
Test: run NetStatsHostTest#testASetThreadStatsUid on a non-default
      user profile.

Change-Id: I4353a383bd898340489e7dd70374a63b2ca0938b
1 file changed