commander: check for valid flag for manual_control

src/modules/commander/ManualControl.cpp

@@ -53,6 +53,7 @@ bool ManualControl::update()
 	}
 
 	_rc_available = _rc_allowed
+			&& _manual_control_setpoint.valid
 			&& _manual_control_setpoint.timestamp != 0
 			&& (hrt_elapsed_time(&_manual_control_setpoint.timestamp) < (_param_com_rc_loss_t.get() * 1_s));