Handle buffer diff base updates and file renames properly for SSH projects (#14989)

Release Notes:

- N/A

---------

Co-authored-by: Conrad <conrad@zed.dev>

crates/assistant/src/slash_command/diagnostics_command.rs

@@ -284,7 +284,7 @@ fn collect_diagnostics(
         PathBuf::try_from(path)
             .ok()
             .and_then(|path| {
-                project.read(cx).worktrees().find_map(|worktree| {
+                project.read(cx).worktrees(cx).find_map(|worktree| {
                     let worktree = worktree.read(cx);
                     let worktree_root_path = Path::new(worktree.root_name());
                     let relative_path = path.strip_prefix(worktree_root_path).ok()?;