fs: Remove unused import (#9344)

Followup to #9341 as I've noticed a CI failure on bundling step of my
other PR
(https://github.com/zed-industries/zed/actions/runs/8283419386/job/22666698264)
Release Notes:

- N/A

crates/fs/src/fs.rs

@@ -11,7 +11,9 @@ use git2::Repository as LibGitRepository;
 use parking_lot::Mutex;
 use repository::GitRepository;
 use rope::Rope;
-use smol::io::{AsyncReadExt, AsyncWriteExt};
+#[cfg(any(test, feature = "test-support"))]
+use smol::io::AsyncReadExt;
+use smol::io::AsyncWriteExt;
 use std::io::Write;
 use std::sync::Arc;
 use std::{