BUG-9675: Advanced LDAP Sync Plugin 1.4.27 Error al editar... IMPROVEMENT

- option import Users enter without having activated the plugin.
- was add validation for option import users.
Merge pull request #1584 from marcoAntonioNina/BUG-9675

BUG-9675: Advanced LDAP Sync Plugin 1.4.27 Error al editar... IMPROVEMENT