ActionView::Template::ErrorProjects::Security::DashboardController#show error No route matches

https://sentry.gitlab.net/gitlab/gitlabcom/issues/803530/

ActionController::UrlGenerationError: No route matches {:action=>"index", :controller=>"groups/security/vulnerabilities", :group_id=>nil, :namespace_id=>"j-steinblock", :project_id=>"slideshow"}, possible unmatched constraints: [:group_id]
  action_dispatch/journey/formatter.rb:55:in `generate'
    raise ActionController::UrlGenerationError, message
  action_dispatch/routing/route_set.rb:748:in `generate'
    @set.formatter.generate(named_route, options, recall, PARAMETERIZE)
  action_dispatch/routing/route_set.rb:779:in `generate'
    Generator.new(route_key, options, recall, self).generate
  action_dispatch/routing/route_set.rb:826:in `url_for'
    path, params = generate(route_name, path_options, recall)
  action_dispatch/routing/route_set.rb:277:in `call'
    t._routes.url_for(hash, route_name, url_strategy)
...
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ActionView::Template::Error: No route matches {:action=>"index", :controller=>"groups/security/vulnerabilities", :group_id=>nil, :namespace_id=>"j-steinblock", :project_id=>"slideshow"}, possible unmatched constraints: [:group_id]

ActionView::Template::Error: No route matches {:action=>"index", :controller=>"groups/security/vulnerabilities", :group_id=>nil, :namespace_id=>"j-steinblock", :project_id=>"slideshow"}, possible unmatched constraints: [:group_id]

ZD: https://gitlab.zendesk.com/agent/tickets/124238 (internal)