Merge branch '423629-delete-service-desk-feature-flag' into 'master'

Delete service_desk_vue_list feature flag

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/144782



Merged-by: Alper Akgun <aakgun@gitlab.com>
Approved-by: Alex Buijs <abuijs@gitlab.com>
Approved-by: Martin Čavoj <mcavoj@gitlab.com>
Approved-by: Alper Akgun <aakgun@gitlab.com>
Reviewed-by: Alex Buijs <abuijs@gitlab.com>
Reviewed-by: Coung Ngo <cngo@gitlab.com>
Reviewed-by: Martin Čavoj <mcavoj@gitlab.com>
Co-authored-by: Coung Ngo <cngo@gitlab.com>