Potential fix for pull request finding 'Variable defined multiple times'

Co-authored-by: Copilot Autofix powered by AI <223894421+github-code-quality[bot]@users.noreply.github.com>

Author: TheRealAgentK

whatsapp/whatsapp.py

@@ -324,7 +324,6 @@ async def execute(self, inputs: Dict[str, Any], context: ExecutionContext):
                     "success": True
                 })
             else:
-                error_msg = "Unknown error"
                 if isinstance(response, dict):
                     error_msg = response.get("error", {}).get("message", "Unknown error")
                 else: