Improve DAST Profiles library UX - Follow-up

The following points discussed in !50576 (merged) and other places should be addressed:

• Improve mobile experience via !51315 (merged)
  • Add CSS utilities to GitLab UI - gl-display-md-inline-flex!
  • Apply them in ee/app/assets/javascripts/security_configuration/dast_profiles/components/dast_profiles_list.vue
  • Replace gl-display-sm-none with gl-display-md-none
• [ ] Add spinner to Pending Validation Badge - As discussed at gitlab-ui#1117 (closed)
  • Add a smaller loader to GlLoadingIcon, or
  • Add the loading prop implemented at gitlab-ui#1117 (closed)
• ~"technical debt"
  • Use DastScanTypeBadge component in ee/app/assets/javascripts/security_configuration/dast_profiles/components/dast_scanner_profiles_list.vue