file_finder: Reduce vertical padding in footer (#31632)

Follow-up to #31542

This PR reduces the vertical padding in the file finders footer. We can
remove this padding as we already apply it just above


https://github.com/zed-industries/zed/blob/a5a116439e711772190b7fb8e5507eb5dbd95237/crates/file_finder/src/file_finder.rs#L1500

This also ensures that the items on the right side have the same padding
to the border as the icon on the left side. Currently, due to the
padding being applied twice, the items on the right side have `pr_4` as
well as `py_4` in practice, which seems a little excessive.

| `main` | This PR |
| --- | --- |
|
![file_finder_main](https://github.com/user-attachments/assets/352d2ac9-04a9-487d-96ca-b009b797809b)
|
![file_finder_pr](https://github.com/user-attachments/assets/c0b44beb-ff2c-4e93-a5b1-2393652a2a58)
|


Release Notes:

- N/A

crates/file_finder/src/file_finder.rs

@@ -1527,7 +1527,6 @@ impl PickerDelegate for FileFinderDelegate {
                 )
                 .child(
                     h_flex()
-                        .p_2()
                         .gap_2()
                         .child(
                             Button::new("open-selection", "Open").on_click(|_, window, cx| {