### Reproduction steps

1. Turn on relative line numbers
2. Start a debugging session and hit an active debug line
3. minimize Zed so the editor element with the active debug line has
zero visible rows

#### Before 

https://github.com/user-attachments/assets/57cc7a4d-478d-481a-8b70-f14c879bd858
#### After 

https://github.com/user-attachments/assets/19614104-f9aa-4b76-886b-1ad4a5985403

Release Notes:

- debugger: Fix a panic that could occur when minimizing Zed