git: Clear set of dirty paths when doing a full status scan (#36181)

Related to #35780 

Release Notes:

- N/A

---------

Co-authored-by: Kirill Bulatov <kirill@zed.dev>

crates/project/src/git_store.rs

@@ -2349,7 +2349,7 @@ impl GitStore {
                         return None;
                     };
 
-                    let mut paths = vec![];
+                    let mut paths = Vec::new();
                     // All paths prefixed by a given repo will constitute a continuous range.
                     while let Some(path) = entries.get(ix)
                         && let Some(repo_path) =
@@ -2358,7 +2358,11 @@ impl GitStore {
                         paths.push((repo_path, ix));
                         ix += 1;
                     }
+                    if paths.is_empty() {
+                        None
+                    } else {
                         Some((repo, paths))
+                    }
                 });
                 tasks.push_back(task);
             }
@@ -4338,7 +4342,8 @@ impl Repository {
                     bail!("not a local repository")
                 };
                 let (snapshot, events) = this
-                    .read_with(&mut cx, |this, _| {
+                    .update(&mut cx, |this, _| {
+                        this.paths_needing_status_update.clear();
                         compute_snapshot(
                             this.id,
                             this.work_directory_abs_path.clone(),
@@ -4568,6 +4573,9 @@ impl Repository {
                 };
 
                 let paths = changed_paths.iter().cloned().collect::<Vec<_>>();
+                if paths.is_empty() {
+                    return Ok(());
+                }
                 let statuses = backend.status(&paths).await?;
 
                 let changed_path_statuses = cx