Remove extra empty space for files when file icons are turned off (#16142)

Closes #16073

<img width="269" alt="image" src="https://github.com/user-attachments/assets/88b7ff9f-17ec-4764-b37a-c218d7ad14ec">

Release Notes:

- Removed extra empty space for files when file icons are turned off ([#16073](https://github.com/zed-industries/zed/issues/16073))