NullPointerException due to command:adb shell service call connectivity 79 -> void unofferNetwork(in INetworkOfferCallback callback)

BUG:238033349

Change-Id: Ic26e48a8a263e9da3f5b12617e454c5072261253
diff --git a/service/src/com/android/server/ConnectivityService.java b/service/src/com/android/server/ConnectivityService.java
old mode 100644
new mode 100755
index 7b5026d..1087f23
--- a/service/src/com/android/server/ConnectivityService.java
+++ b/service/src/com/android/server/ConnectivityService.java
@@ -6955,6 +6955,7 @@
 
     @Override
     public void unofferNetwork(@NonNull final INetworkOfferCallback callback) {
+        Objects.requireNonNull(callback);
         mHandler.sendMessage(mHandler.obtainMessage(EVENT_UNREGISTER_NETWORK_OFFER, callback));
     }