Clean up handling of NetworkCapabilities#administratorUids.

Update ConnectivityService's check for administrator UIDs to use
ArrayUtils to check for UID inclusion. Update the NetworkCapabilities
annotation on the administrator UIDs field to clarify that it is
NonNull.

Bug: 147903575
Test: atest FrameworksNetTests
Change-Id: Id630fe9d76aacdaf038fdaa5360f0327520ee0c3

core/java/android/net/NetworkCapabilities.java

@@ -882,7 +882,7 @@ public final class NetworkCapabilities implements Parcelable {
      * empty unless the destination is 1) the System Server, or 2) Telephony. In either case, the
      * receiving entity must have the ACCESS_FINE_LOCATION permission and target R+.
      */
-    private int[] mAdministratorUids = new int[0];
+    @NonNull private int[] mAdministratorUids = new int[0];
 
     /**
      * Sets the int[] of UIDs that are administrators of this network.

services/core/java/com/android/server/ConnectivityService.java

@@ -7953,11 +7953,7 @@ public class ConnectivityService extends IConnectivityManager.Stub
 
         // Administrator UIDs also contains the Owner UID
         final int[] administratorUids = nai.networkCapabilities.getAdministratorUids();
-        for (final int uid : administratorUids) {
-            if (uid == callbackUid) return true;
-        }
-
-        return false;
+        return ArrayUtils.contains(administratorUids, callbackUid);
     }
 
     @Override