Add the project search as an item in the status bar (#28388)

Was chatting with @wilhelmklopp, he pointed out that our current
UI-accessible way to access the project search was pretty obscure.


<img width="393" alt="Screenshot 2025-04-08 at 6 57 51 PM"
src="https://github.com/user-attachments/assets/636053cd-5a88-4a5e-8155-6d41d189b7db"
/>

Release Notes:

- Added a button to open the project search to the status bar

crates/zed/src/zed.rs

@@ -222,6 +222,7 @@ pub fn initialize_workspace(
             }
         });
 
+        let search_button = cx.new(|_| search::search_status_button::SearchButton::new());
         let diagnostic_summary =
             cx.new(|cx| diagnostics::items::DiagnosticIndicator::new(workspace, cx));
         let activity_indicator = activity_indicator::ActivityIndicator::new(
@@ -239,6 +240,7 @@ pub fn initialize_workspace(
         let cursor_position =
             cx.new(|_| go_to_line::cursor_position::CursorPosition::new(workspace));
         workspace.status_bar().update(cx, |status_bar, cx| {
+            status_bar.add_left_item(search_button, window, cx);
             status_bar.add_left_item(diagnostic_summary, window, cx);
             status_bar.add_left_item(activity_indicator, window, cx);
             status_bar.add_right_item(inline_completion_button, window, cx);