Prepare 16.9.6 release for omnibus-gitlab-jh

Release issue: https://jihulab.com/gitlab-cn/release/tasks/-/issues/155

Summary

This MR prepares 16-9-stable-jh for 16.9.6.

Automated cherry-picking

Merge requests labeled ~"Pick into 16.9" should be automatically picked into this MR.

Manual intervention

If merge requests cannot be picked automatically they have to be created manually targeting 16-9-stable-jh-patch-6.

---

See also Patch Releases documentation.