feat: allow preloading selectionElements (#243)

Author: rk132

Runtime/AvatarCreator/Scripts/UI/Elements/SelectionElement.cs

@@ -19,7 +19,22 @@ public abstract class SelectionElement : MonoBehaviour
         [SerializeField] private SelectionButton buttonElementPrefab;
         [SerializeField] private GameObject selectedIconPrefab;
         [SerializeField] private Transform buttonContainer;
-        private GameObject selectedIcon;
+
+        private GameObject _selectedIcon;
+        private GameObject selectedIcon
+        {
+            get
+            {
+                if (_selectedIcon)
+                {
+                    return _selectedIcon;
+                }
+                _selectedIcon = Instantiate(selectedIconPrefab, buttonContainer);
+                selectedIcon.SetActive(false);
+                return _selectedIcon;
+            }
+        }
+        
 
         [Space(5)]
         [Header("Events")]
@@ -28,12 +43,6 @@ public abstract class SelectionElement : MonoBehaviour
 
         protected Transform ButtonContainer => buttonContainer;
 
-        private void Start()
-        {
-            selectedIcon = Instantiate(selectedIconPrefab, buttonContainer);
-            selectedIcon.SetActive(false);
-        }
-
         /// <summary>
         /// Creates button elements for each asset in the provided array.
         /// This function is generic and can work with any asset type that implements the IAssetData interface.