Fix skinned model retarget source asset filter to work after AssetPicker refactor with new validator

Source/Editor/GUI/AssetPicker.cs

@@ -38,11 +38,6 @@ namespace FlaxEditor.GUI
         /// </summary>
         public event Action SelectedItemChanged;
 
-        /// <summary>
-        /// The custom callback for assets validation. Cane be used to implement a rule for assets to pick.
-        /// </summary>
-        public Func<ContentItem, bool> CheckValid;
-
         /// <summary>
         /// False if changing selected item is disabled.
         /// </summary>

Source/Editor/Windows/Assets/SkinnedModelWindow.cs

@@ -272,7 +272,7 @@ namespace FlaxEditor.Windows.Assets
                         infoLabel.AutoHeight = true;
                         var sourceAssetPicker = setupGroup.AddPropertyItem("Source Asset").Custom<AssetPicker>().CustomControl;
                         sourceAssetPicker.Height = 48;
-                        sourceAssetPicker.CheckValid = CheckSourceAssetValid;
+                        sourceAssetPicker.Validator.CheckValid = CheckSourceAssetValid;
                         sourceAssetPicker.SelectedItemChanged += () =>
                         {
                             proxy.Setups.Add(sourceAssetPicker.Validator.SelectedAsset, new SetupProxy());