Migrate deprecated bs-callout to alert component in pages

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/144351



Merged-by: Zack Cuddy <zcuddy@gitlab.com>
Approved-by: Zack Cuddy <zcuddy@gitlab.com>
Approved-by: Thomas Randolph <trandolph@gitlab.com>
Co-authored-by: Taras Taday <ttaday@softserveinc.com>