Merge branch 'jnnkl-duo-multi-slash' into 'master'

Adapt Duo Chat Slash commands for multi-threaded

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/183822



Merged-by: Kushal Pandya <kushal@gitlab.com>
Approved-by: Doug Stull <dstull@gitlab.com>
Approved-by: Kushal Pandya <kushal@gitlab.com>
Reviewed-by: Doug Stull <dstull@gitlab.com>
Reviewed-by: Jannik Lehmann <jlehmann@gitlab.com>
Co-authored-by: Jannik Lehmann <jlehmann@gitlab.com>