Fix a bug where updates of offers won't find existing offers

.equals() only work on cross-process Binder instances if casted to
a Binder instance first.

Bug: 184281544
Test: ConnectivityServiceTest. CTS test for this specific issue to come
Merged-In: I3c2563d4ae4e3715d0c6270344ba8f7ef067872f
Merged-In: I7b9e0df21a3cca59659867a75792289ddee2f1d7
Change-Id: I7b9e0df21a3cca59659867a75792289ddee2f1d7
  (cherry-picked from ag/14125149)

service/src/com/android/server/ConnectivityService.java

@@ -6698,7 +6698,7 @@ public class ConnectivityService extends IConnectivityManager.Stub
             @NonNull final INetworkOfferCallback callback) {
         ensureRunningOnConnectivityServiceThread();
         for (final NetworkOfferInfo noi : mNetworkOffers) {
-            if (noi.offer.callback.equals(callback)) return noi;
+            if (noi.offer.callback.asBinder().equals(callback.asBinder())) return noi;
         }
         return null;
     }