Pass formats explicitly when rendering .md file

Changelog: other
EE: true

ee/app/services/issues/create_from_vulnerability_data_service.rb

@@ -36,6 +36,7 @@ module Issues
     def render_description(vulnerability)
       ApplicationController.render(
         template: 'vulnerabilities/issue_description',
+        formats: :md,
         locals: { vulnerability: vulnerability }
       )
     end