Fix ConnectivityServiceTest fail.

NetdService#getInstance() will get null object in
WrappedConnectivityService constructor. Then pass this null
INetd object to PermissionMonitor will case NPE in
PermissionMonitor#sendPackagePermissionsToNetd()

Bug: None
Test: atest FrameworksNetTests
Change-Id: Ia1c80f9600a19c4aaf3f3c1b497b355d96c49c8e
diff --git a/services/core/java/com/android/server/connectivity/PermissionMonitor.java b/services/core/java/com/android/server/connectivity/PermissionMonitor.java
index 31b96ca..b9f1748 100644
--- a/services/core/java/com/android/server/connectivity/PermissionMonitor.java
+++ b/services/core/java/com/android/server/connectivity/PermissionMonitor.java
@@ -466,7 +466,10 @@
      */
     @VisibleForTesting
     void sendPackagePermissionsToNetd(SparseIntArray netdPermissionsAppIds) {
-
+        if (mNetd == null) {
+            Log.e(TAG, "Failed to get the netd service");
+            return;
+        }
         ArrayList<Integer> allPermissionAppIds = new ArrayList<>();
         ArrayList<Integer> internetPermissionAppIds = new ArrayList<>();
         ArrayList<Integer> updateStatsPermissionAppIds = new ArrayList<>();