Make GitRepository::status async and remove cx parameter (#27514)

This lays the groundwork for using `status` as part of the new agent
panel.

Release Notes:

- N/A

crates/project/src/project.rs

@@ -1476,7 +1476,7 @@ impl Project {
     ) -> Entity<Project> {
         use clock::FakeSystemClock;
 
-        let fs = Arc::new(RealFs::default());
+        let fs = Arc::new(RealFs::new(None, cx.background_executor().clone()));
         let languages = LanguageRegistry::test(cx.background_executor().clone());
         let clock = Arc::new(FakeSystemClock::new());
         let http_client = http_client::FakeHttpClient::with_404_response();