Fix ldap_sync_worker_cron and geo_bulk_notify_worker_cron add ldap_group_sync_worker

• Both conditional statements for ldap_sync_worker_cron and geo_bulk_notify_worker_cron where incorrectly checking the configuration options without the _cron string. Meaning these settings where never applied correctly. - This was broken in ea165078 (4 months ago) ldap_sync_worker_cron has been broken since 8.16.0.

• Add the additional setting ldap_group_sync_worker documented in https://docs.gitlab.com/ee/administration/auth/ldap.html#adjusting-ldap-user-and-group-sync-schedules and included in GitLab EE.