draw2d.io.Reader.unmarshal doesn't work properly for Hub components

# Description

When the draw2d.io.Reader.unmarshal function retrieves a JSON document, the ports are incorrectly mapped to the hub component. All the connections focus on the central port on the hub. 
<img width="727" alt="Screenshot 2024-12-19 at 16 12 41" src="https://github.com/user-attachments/assets/662a27bc-a7d7-4dbd-9922-b0ee5780ab0c" />



