baskcstage uses k8s style resource name for referencing catalog entities. It is of the form 'kind:namespace:name'. However, there's no real support for namespaces. It is always 'default'.

This issue causes confusion among users and developers when specifying users and groups in 'create notification request'.

The backstage API used by BE plugin provides the user name with the namespace.

Therefore, we would like to require that the users and groups in 'create notification' to be of the same format.