Merge branch 'rename-explain_vulnerability-tool' into 'master'

Rename /explain_vulnerability Duo slash command

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/156030



Merged-by: Joe Woodward <jwoodward@gitlab.com>
Approved-by: David Pisek <dpisek@gitlab.com>
Approved-by: Joseph Wambua <jjoshua@gitlab.com>
Approved-by: Samantha Ming <sming@gitlab.com>
Approved-by: Joe Woodward <jwoodward@gitlab.com>
Co-authored-by: Alex Buijs <abuijs@gitlab.com>