editor: Improve multibuffer header spacing (#42071)

BEFORE:
<img width="1751" height="629" alt="image"
src="https://github.com/user-attachments/assets/f88464d3-5daa-4d53-b394-f92db8b0fd8c"
/>

AFTER:
<img width="1714" height="493" alt="image"
src="https://github.com/user-attachments/assets/022c883b-b219-40a3-aa5f-0c16d23e8abf"
/>

Release Notes:

- N/A

---------

Co-authored-by: Danilo Leal <daniloleal09@gmail.com>
5ced3ef0fdLibon committed on 11/6/2025, 2:09:06 PM· committed by GitHubparent7a37dd9
1 file changedLine totals unavailable