Cancel a specific order by its client order ID.
Args: account_name: Name of the account connector_name: Name of the connector client_order_id: Client order ID to cancel trading_pair: Trading pair for the order accounts_service: Injected accounts service
Returns: Success message with cancelled order ID
Raises: HTTPException: 404 if account/connector not found, 500 for cancellation errors
Basic authentication header of the form Basic <encoded-value>, where <encoded-value> is the base64-encoded string username:password.
Successful Response