Merge branch '467673-policies-disable-submit-pipeline-execution' into 'master'

Disable form submit when validation fails

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/156528



Merged-by: Artur Fedorov <afedorov@gitlab.com>
Approved-by: Martin Čavoj <mcavoj@gitlab.com>
Approved-by: Paul Gascou-Vaillancourt <pgascouvaillancourt@gitlab.com>
Reviewed-by: Artur Fedorov <afedorov@gitlab.com>
Reviewed-by: Martin Čavoj <mcavoj@gitlab.com>