Further subgraph improvements (#6466)

- Prune disconnected widgets on config panel open
- Fix breakage of DOMWidgets on double nest
- Fix self clipping of proxied DOMWidget nodes
- Blacklist cloning of promtoed widget prop

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-6466-Further-subgraph-improvements-29c6d73d365081c8b63dda068486805c)
by [Unito](https://www.unito.io)

src/components/graph/widgets/DomWidget.vue

@@ -143,8 +143,8 @@ onMounted(() => {
     widget.options.selectOn ?? ['focus', 'click'],
     () => {
       const lgCanvas = canvasStore.canvas
-      lgCanvas?.selectNode(widget.node)
-      lgCanvas?.bringToFront(widget.node)
+      lgCanvas?.selectNode(widgetState.widget.node)
+      lgCanvas?.bringToFront(widgetState.widget.node)
     }
   )
 })