backend: Add request as parameter to json_success.

Adds request as a parameter to json_success as a refactor towards
making `ignored_parameters_unsupported` functionality available
for all API endpoints.

Also, removes any data parameters that are an empty dict or
a dict with the generic success response values.

zerver/webhooks/helloworld/view.py

@@ -32,4 +32,4 @@ def api_helloworld_webhook(
     # send the message
     check_send_webhook_message(request, user_profile, topic, body)
 
-    return json_success()
+    return json_success(request)