setMode abstract method
- required String deviceId,
 - required Code39Mode mode,
 
Sets the mode for Code 39 symbology.
deviceId - The identifier of the target device.
mode - The Code39Mode enum value representing the desired mode.
Returns a CommandResponse indicating the success or failure of the operation.
Implementation
Future<CommandResponse> setMode({
  required String deviceId,
  required Code39Mode mode,
});