title: Drawing the default inspector with UIElements/UI Builder
body: <p>I have a <code>LevelEditor</code> script which has a custom inspector editor built with UIBuilder and UIElements.
  The problem is that i would like to cache references inside a list but i do not want to make a custom list view for it (it's kinda hard to implement in UIElements and not worth the time) so i thought i would just make the <code>private List&lt;MyType&gt; _myVar;</code> as <code>[Serializefield]</code> and then draw the <strong>DefaultInspector</strong> below the custom one.</p>
  <p>I found a method that does this <a href="https://docs.unity3d.com/ScriptReference/Editor.DrawDefaultInspector.html" rel="nofollow noreferrer">DrawDefaultInspector</a> but unfortunately it does nothing.</p>
  <pre><code>public override VisualElement CreateInspectorGUI()
  {
      _visualTree.CloneTree(_rootElement);
  
      // My custom editor code
      ...
  
      DrawDefaultInspector();
  
      return _rootElement;
  }
  </code></pre>
  <p>Any help is appreciated...</p>