Feat: Vue Node Slot Improvements (#6359)

## Summary

Several fixes and improvements to the slot behavior on Vue nodes.

## Changes

- **What**: Restore the pseudo-slots, if there are slots being hidden by
collapse
- **What**: Connections while collapsed
- **What**: Display the links in a more reasonable location
- **What**: Fixes styling of linked widgets
- **What**: [~Fix reconnecting logic to prioritize newly disconnected
and now empty
slots~](https://github.com/Comfy-Org/ComfyUI_frontend/pull/6370)

## Review Focus

<!-- Critical design decisions or edge cases that need attention -->

<!-- If this PR fixes an issue, uncomment and update the line below -->
<!-- Fixes #ISSUE_NUMBER -->

## Screenshots (if applicable)


https://github.com/user-attachments/assets/913cfb8f-acdd-4f3d-b619-c280cc11cce5


<!-- Add screenshots or video recording to help explain your changes -->

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-6359-WIP-Collapsed-nodes-multislots-29b6d73d3650817289d5f0a8efdade84)
by [Unito](https://www.unito.io)

---------

Co-authored-by: github-actions <github-actions@github.com>

src/renderer/core/canvas/links/linkConnectorAdapter.ts

@@ -154,10 +154,13 @@ export function createLinkConnectorAdapter(): LinkConnectorAdapter | null {
   const graph = app.canvas?.graph
   const connector = app.canvas?.linkConnector
   if (!graph || !connector) return null
-  let adapter = adapterByGraph.get(graph)
-  if (!adapter || adapter.linkConnector !== connector) {
-    adapter = new LinkConnectorAdapter(graph, connector)
-    adapterByGraph.set(graph, adapter)
+
+  const adapter = adapterByGraph.get(graph)
+  if (adapter && adapter.linkConnector === connector) {
+    return adapter
   }
-  return adapter
+
+  const newAdapter = new LinkConnectorAdapter(graph, connector)
+  adapterByGraph.set(graph, newAdapter)
+  return newAdapter
 }