bugfix for eye tracking

Source/StudyFrameworkPlugin/Private/GazeTracking/SFGazeTracker.cpp

@@ -168,7 +168,7 @@ FGazeRay USFGazeTracker::GetLocalGazeDirection()
 
 FGazeRay USFGazeTracker::GetWorldGazeDirection()
 {
-	if (GazeTrackingBackend == EGazeTrackingBackend::OpenXREyeTracker) {
+	if (bEyeTrackingStarted && GazeTrackingBackend == EGazeTrackingBackend::OpenXREyeTracker) {
 		//this is already in world coordinates
 		return GetGazeRayFromEyeTrackerData();
 	}