Merge branch 'docs-clarify-auth-token-runner-usage' into 'master'

Add more clarity about using new authentication token

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/122633



Merged-by: Fiona Neill <fneill@gitlab.com>
Approved-by: Vladimir Shushlin <vshushlin@gitlab.com>
Approved-by: Fiona Neill <fneill@gitlab.com>
Reviewed-by: Pedro Pombeiro <noreply@pedro.pombei.ro>
Co-authored-by: Alexandr Tanayno <atanayno@gitlab.com>
Co-authored-by: Vladimir Shushlin <vshushlin@gitlab.com>