Bring SAST to Core - brakeman

This change allows customers, regardless of tier, to enable the SAST
vendored template and to start leveraging the brakeman analyzer.

changelogs/unreleased/rf-brakeman-to-core.yml

+---
+title: Bring SAST to Core - brakeman
+merge_request: 34217
+author:
+type: added

lib/gitlab/ci/templates/Security/SAST.gitlab-ci.yml

@@ -80,7 +80,6 @@ brakeman-sast:
     - if: $SAST_DISABLED || $SAST_DISABLE_DIND == 'false'
       when: never
     - if: $CI_COMMIT_BRANCH &&
-          $GITLAB_FEATURES =~ /\bsast\b/ &&
           $SAST_DEFAULT_ANALYZERS =~ /brakeman/
       exists:
         - 'config/routes.rb'