Fix missing uniqueId for some asset types

AssetStudioGUI/Components/AssetItem.cs

@@ -5,6 +5,8 @@ namespace AssetStudioGUI
 {
     internal class AssetItem : ListViewItem
     {
+        private static long _counter;
+
         public Object Asset;
         public SerializedFile SourceFile;
         public string Container = string.Empty;
@@ -13,7 +15,7 @@ namespace AssetStudioGUI
         public long FullSize;
         public ClassIDType Type;
         public string InfoText;
-        public string UniqueID;
+        public readonly string UniqueID;
         public ulong Hash;
         public GameObjectTreeNode TreeNode;
 
@@ -25,6 +27,7 @@ namespace AssetStudioGUI
             TypeString = Type.ToString();
             m_PathID = asset.m_PathID;
             FullSize = asset.byteSize;
+            UniqueID = $" #{_counter++}";
             Hash = 0;
         }
 
@@ -38,5 +41,10 @@ namespace AssetStudioGUI
                 FullSize.ToString(), //Size
             });
         }
+
+        public static void Reset()
+        {
+            _counter = 0;
+        }
     }
 }