Merge branch '454286_update_documentation' into 'master'

Clarify that Password authentication must be enabled for OAuth flow

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/149965



Merged-by: Ashraf Khamis <akhamis@gitlab.com>
Co-authored-by: Vasilii Iakliushin <viakliushin@gitlab.com>