fs: add missing call to uv_fs_req_cleanup

Always call uv_fs_req_cleanup after calling uv_fs_open instead of just when uv_fs_open returns a negative result. I referenced ReadFileSync from node:js2c when making this change. https://github.com/bnoordhuis made the same suggestion based on the PR #49691. Fixes: #57800 PR-URL: #57811 Reviewed-By: Matteo Collina <matteo.collina@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> CVE-ID: CVE-2025-23165

Author: Justin-Nietzel

src/node_file.cc

@@ -2615,9 +2615,9 @@ static void ReadFileUtf8(const FunctionCallbackInfo<Value>& args) {
  FS_SYNC_TRACE_END(open);
  if (req.result < 0) {
  uv_fs_req_cleanup(&req);
- // req will be cleaned up by scope leave.
  return env->ThrowUVException(req.result, "open", nullptr, path.out());
  }
+ uv_fs_req_cleanup(&req);
  }
 
  auto defer_close = OnScopeLeave([file, is_fd, &req]() {