Optimize file finder subscriptions (#8343)

Fixes #7519 

Optimizes file finder subscriptions — it now only subscribes to
worktrees updates instead of all project updates.

Project panel could also be optimized this way, I guess.

Release Notes:

- Fix selection resets in the file finder during language server
startup ([7519](https://github.com/zed-industries/zed/issues/7519))

crates/file_finder/src/file_finder.rs

@@ -365,14 +365,7 @@ impl FileFinderDelegate {
         history_items: Vec<FoundPath>,
         cx: &mut ViewContext<FileFinder>,
     ) -> Self {
-        cx.observe(&project, |file_finder, _, cx| {
-            //todo We should probably not re-render on every project anything
-            file_finder
-                .picker
-                .update(cx, |picker, cx| picker.refresh(cx))
-        })
-        .detach();
-
+        Self::subscribe_to_updates(&project, cx);
         Self {
             file_finder,
             workspace,
@@ -389,6 +382,20 @@ impl FileFinderDelegate {
         }
     }
 
+    fn subscribe_to_updates(project: &Model<Project>, cx: &mut ViewContext<FileFinder>) {
+        cx.subscribe(project, |file_finder, _, event, cx| {
+            match event {
+                project::Event::WorktreeUpdatedEntries(_, _)
+                | project::Event::WorktreeAdded
+                | project::Event::WorktreeRemoved(_) => file_finder
+                    .picker
+                    .update(cx, |picker, cx| picker.refresh(cx)),
+                _ => {}
+            };
+        })
+        .detach();
+    }
+
     fn spawn_search(
         &mut self,
         query: PathLikeWithPosition<FileSearchQuery>,