FlightTaskAuto: Nudging: only set yawrate_sp if WV is disabled or stick out of dead-zone

Otherwise the setpoint from weather vane is constantly overwritten by it,
even if the yaw stick is not moved.

Signed-off-by: Silvan Fuhrer <silvan@auterion.com>

src/modules/flight_mode_manager/tasks/Auto/FlightTaskAuto.cpp

@@ -249,8 +249,14 @@ void FlightTaskAuto::_prepareLandSetpoints()
 		// Stick full up -1 -> stop, stick full down 1 -> double the speed
 		vertical_speed *= (1 + _sticks.getPositionExpo()(2));
 
-		_stick_yaw.generateYawSetpoint(_yawspeed_setpoint, _land_heading,
-					       _sticks.getPositionExpo()(3) * math::radians(_param_mpc_man_y_max.get()), _yaw, _is_yaw_good_for_control, _deltatime);
+		// Only set a yawrate setpoint if weather vane is not active or the yaw stick is out of its dead-zone
+		const bool weather_vane_active = (_ext_yaw_handler != nullptr) && _ext_yaw_handler->is_active();
+
+		if (!weather_vane_active || fabsf(_sticks.getPositionExpo()(3)) > FLT_EPSILON) {
+			_stick_yaw.generateYawSetpoint(_yawspeed_setpoint, _land_heading,
+						       _sticks.getPositionExpo()(3) * math::radians(_param_mpc_man_y_max.get()), _yaw, _is_yaw_good_for_control, _deltatime);
+		}
+
 		_stick_acceleration_xy.generateSetpoints(_sticks.getPositionExpo().slice<2, 1>(0, 0), _yaw, _land_heading, _position,
 				_velocity_setpoint_feedback.xy(), _deltatime);
 		_stick_acceleration_xy.getSetpoints(_land_position, _velocity_setpoint, _acceleration_setpoint);