FlightTaskAuto: merge activate(), reActivate() and update() from FlightTaskAutoLineSmoothVel

src/modules/flight_mode_manager/tasks/AutoFollowMe/FlightTaskAutoFollowMe.cpp

@@ -42,9 +42,8 @@ using namespace matrix;
 
 bool FlightTaskAutoFollowMe::update()
 {
-	bool ret = FlightTaskAuto::update();
 	_position_setpoint = _target;
 	matrix::Vector2f vel_sp = _getTargetVelocityXY();
 	_velocity_setpoint = matrix::Vector3f(vel_sp(0), vel_sp(1), 0.0f);
-	return ret;
+	return true;
 }