Can't connect the output/input to the subgraph slot in Vue nodes.

https://github.com/user-attachments/assets/f5b9f3d6-6614-4b25-ba92-518e612785e4

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-5706-Can-t-connect-the-output-input-to-the-subgraph-slot-in-Vue-nodes-2746d73d3650813882b9f5a501ff2988) by [Unito](https://www.unito.io)
