Given a chat group trying to dock a chat to the bottom shows a drag affordance that doesn't work

Testing #331068

<img width="2880" height="1708" alt="Image" src="https://github.com/user-attachments/assets/53a77f52-ff0b-4413-821d-3af5402635c8" />



Compared to editor layouts which are smart enough just to not offer a drag affordance for this

