🐛 ensure payload is initialized before adding thread_name in async and sync webhooks

Author: Paillat-dev

discord/webhook/async_.py

@@ -345,6 +345,7 @@ def execute_webhook(
             params["thread_id"] = thread_id
 
         if thread_name:
+            payload = payload or {}
             payload["thread_name"] = thread_name
 
         route = Route(

discord/webhook/sync.py

@@ -315,6 +315,7 @@ def execute_webhook(
             params["thread_id"] = thread_id
 
         if thread_name:
+            payload = payload or {}
             payload["thread_name"] = thread_name
 
         route = Route(