Commander: ignore MAV_CMD_REQUEST_MSG

This commit adds the MAV_CMD_REQUEST_MESSAGE to the list of vehicle
commands which are ignored without generating a warning sound.

src/modules/commander/Commander.cpp

@@ -1587,6 +1587,7 @@ Commander::handle_command(const vehicle_command_s &cmd)
 	case vehicle_command_s::VEHICLE_CMD_DO_GIMBAL_MANAGER_CONFIGURE:
 	case vehicle_command_s::VEHICLE_CMD_CONFIGURE_ACTUATOR:
 	case vehicle_command_s::VEHICLE_CMD_DO_SET_ACTUATOR:
+	case vehicle_command_s::VEHICLE_CMD_REQUEST_MESSAGE:
 		/* ignore commands that are handled by other parts of the system */
 		break;