Unauthorized route migration for routes owned by stack-monitoring (#214787)

## Summary

Passed security config to the core router, so it is correctly captured.


### Checklist

- [x] The PR description includes the appropriate Release Notes section,
and the correct `release_note:*` label is applied per the
[guidelines](https://www.elastic.co/guide/en/kibana/master/contributing.html#kibana-release-notes-process)

x-pack/platform/plugins/private/monitoring/server/plugin.ts

@@ -411,6 +411,7 @@ export class MonitoringPlugin
         const routeConfig = {
           path: options.path,
           validate: options.validate,
+          security: options.security,
         };
 
         if (method.toLowerCase() === 'post') {