The PR matches project search layout with the recent changes in the
buffer project layout.

https://github.com/zed-industries/zed/assets/2101250/91b905ea-aed8-4740-9e60-67f3052885e2


Release Notes:

- Improve project search bar layout, match it with the buffer search bar ([7722](https://github.com/zed-industries/zed/issues/7722))