recent projects: cleanup ui (#7528)

As the ui for the file finder was recently changed in #7364, I think it
makes sense to also update the ui of the recent projects overlay.

Before:

![image](https://github.com/zed-industries/zed/assets/53836821/8a0f5bef-9b37-40f3-a974-9dfd7833cc71)

After:

![image](https://github.com/zed-industries/zed/assets/53836821/7e9f934a-1ac3-4716-b7b6-67a7435f3bde)


Release Notes:

- Improved UI of recent project overlay

crates/project_symbols/src/project_symbols.rs

@@ -25,7 +25,7 @@ pub fn init(cx: &mut AppContext) {
                 let handle = cx.view().downgrade();
                 workspace.toggle_modal(cx, move |cx| {
                     let delegate = ProjectSymbolsDelegate::new(handle, project);
-                    Picker::new(delegate, cx).width(rems(34.))
+                    Picker::uniform_list(delegate, cx).width(rems(34.))
                 })
             });
         },
@@ -344,7 +344,7 @@ mod tests {
 
         // Create the project symbols view.
         let symbols = cx.new_view(|cx| {
-            Picker::new(
+            Picker::uniform_list(
                 ProjectSymbolsDelegate::new(workspace.downgrade(), project.clone()),
                 cx,
             )