Closes https://github.com/zed-industries/zed/issues/43726

Note that the truncation strategy on the file path is not yet perfect.
I'm just applying the regular method from the label component, but we
should wrap path text from the start rather than from the end. Some time
in the future!

<img width="500" height="712" alt="Screenshot 2025-11-28 at 7  17@2x"
src="https://github.com/user-attachments/assets/6ebc618a-4b4a-42fd-b5b7-39fec3ae5335"
/>

Release Notes:

- Fixed a bug where the "Open File" button would overflow in the
multibuffer header if the file path was too long.