urn:ietf:params:scim:schemas:extension:enterprise:2.0:User is not handled consistently

[davidsarosap]

The standard extension "urn:ietf:params:scim:schemas:extension:enterprise:2.0:User" is not determined as a core schema (see this), but the definition is contained in the core schema (see this and this).

This is somehow not consistent and leads to an incorrect handling here.
It is determine as custom schema, but the definition lays in the "core schema import".