fix scroll error

AwesomeUIWidgets/Assets/Scripts/ChatPage.cs

 using Unity.UIWidgets.painting;
 using Unity.UIWidgets.rendering;
 using Unity.UIWidgets.widgets;
-using UnityEditor.Build.Content;
-using Random = System.Random;
-using TextStyle = Unity.UIWidgets.ui.TextStyle;
 
 namespace UIWidgetsSample
 

AwesomeUIWidgets/Assets/Scripts/Widgets/chat_list.cs

                    {
                        if (_oldIndex != null && _oldIndex.Count != 0 && !_oldIndex.Contains(message1.id))
                        {
-                           _listKey.currentState?.insertItem(0);
+                           _listKey.currentState?.insertItem(_oldIndex.Count -1);
                        }
                    }
                 }