Merge branch '20250221-clavimoniere-518138-two-factor-auth-header-accessibility' into 'master'

Use semantic H3 for "Can't scan the code" section of 2FA setup

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/182336



Merged-by: Lorenz van Herwaarden <lvanherwaarden@gitlab.com>
Approved-by: Lorenz van Herwaarden <lvanherwaarden@gitlab.com>
Approved-by: Fernando Cardenas <14022659-fernando-c@users.noreply.gitlab.com>
Co-authored-by: Chad Lavimoniere <clavimoniere@gitlab.com>