Default role assignments for demo users are created even when no demo users are present

[rhafer]

Describe the bug

Even when not creating the demo users on startup we still create the default role assignments for them.

Steps to reproduce

Start ocis without creating the demo users

List role assignment for demo user (moss) in this case:

curl -k -u admin:admin https://localhost:9200/api/v0/settings/assignments-list -X POST --data '{"account_uuid": "058bff95-6708-4fe5-91e4-9ea3d377588b"}'
{
  "assignments": [
    {
      "id": "8ac44d80-d1a6-4e5f-b1ac-b054071cc02d",
      "accountUuid": "058bff95-6708-4fe5-91e4-9ea3d377588b",
      "roleId": "71881883-1768-46bd-a24d-a356a2afdf7f"
    }
  ]
}