Fix toolbar spacing regressions (#29964)

Cleaning up as I introduced a few regressions in this PR:
https://github.com/zed-industries/zed/pull/29866.

Release Notes:

- N/A

crates/git_ui/src/project_diff.rs

@@ -893,9 +893,8 @@ impl Render for ProjectDiffToolbar {
 
         h_group_xl()
             .my_neg_1()
-            .items_center()
             .py_1()
-            .px_2()
+            .items_center()
             .flex_wrap()
             .justify_between()
             .child(