Create correct TabControl containers.

src/Avalonia.Controls/TabControl.cs

@@ -165,6 +165,9 @@ namespace Avalonia.Controls
             return RegisterContentPresenter(presenter);
         }
 
+        protected internal override Control CreateContainerOverride() => new TabItem();
+        protected internal override bool IsItemItsOwnContainerOverride(Control item) => item is TabItem;
+
         protected internal override void PrepareContainerForItemOverride(Control element, object? item, int index)
         {
             base.PrepareContainerForItemOverride(element, item, index);