fix github_token validation on reply and close issue

app.py

@@ -805,7 +805,9 @@ def reply_and_close_issue(
     """
     
     if not github_token:
-        raise gr.Error("⚠️ Write Permission Error: A GitHub Token is mandatory for posting comments or closing issues.")
+        error = "Write Permission Error: A GitHub Token is mandatory for posting comments or closing issues."
+        gr.Info(f"⚠️ {error}")
+        return error
     
     if not repo_url:
         error = "Please provide the repository URL."