Fixed forwarding to swizzled method in Instance ID on iOS.

When importing the Instance ID C++ SDK the swizzling of
application:didRegisterForRemoteNotificationsWithDeviceToken:
would no longer call the swizzled out method.  This fixes this
to forward to the original implementation.
PiperOrigin-RevId: 248783081

Author: smiles

instance_id/src/ios/instance_id.mm

@@ -111,6 +111,14 @@ static void AppDelegateApplicationDidRegisterForRemoteNotificationsWithDeviceTok
     id self, SEL selector_value, UIApplication *application, NSData *device_token) {
   LogDebug("Caching device token");
   g_device_token = device_token;
+  IMP app_delegate_application_did_register_for_remote_notifications_with_device_token =
+      SwizzledMethodCache().GetMethodForObject(
+          self, @selector(application:didRegisterForRemoteNotificationsWithDeviceToken:));
+  if (app_delegate_application_did_register_for_remote_notifications_with_device_token) {
+    ((util::AppDelegateApplicationDidRegisterForRemoteNotificationsWithDeviceTokenFunc)
+         app_delegate_application_did_register_for_remote_notifications_with_device_token)(
+        self, selector_value, application, device_token);
+  }
 }
 // Hook all AppDelegate methods that IID requires to cache data for token fetch operations.
 //