Revert "removed condition"

This reverts commit f5e5656083fa8581a1af51421c8a5e3e2380f22a.

Assets/Scenes/ImageTracking/Multi Prefab - Image Tracking/MultiTrackedImageInfoManager.cs

         public void SetPrefabForReferenceImage(XRReferenceImage referenceImage, GameObject alternativePrefab)
         {
             m_PrefabsDictionary[referenceImage.guid] = alternativePrefab;
-            var instantiatedPrefab = m_Instantiated[referenceImage.guid];
-            m_Instantiated[referenceImage.guid] = Instantiate(alternativePrefab, instantiatedPrefab.transform.parent);
-            Destroy(instantiatedPrefab);
+            if (m_Instantiated.TryGetValue(referenceImage.guid, out GameObject instantiatedPrefab))
+            {
+                m_Instantiated[referenceImage.guid] = Instantiate(alternativePrefab, instantiatedPrefab.transform.parent);
+                Destroy(instantiatedPrefab);
+            }
         }
 
 #if UNITY_EDITOR

ProjectSettings/ProjectSettings.asset

     16:9: 1
     Others: 1
   bundleVersion: 0.1
-  preloadedAssets: []
+  preloadedAssets:
+  - {fileID: -6122771651556369562, guid: e2f869774b12e400996eb546603602e3, type: 2}
+  - {fileID: 4800000, guid: c9f956787b1d945e7b36e0516201fc76, type: 3}
   metroInputSource: 0
   wsaTransparentSwapchain: 0
   m_HolographicPauseOnTrackingLoss: 1