GraphQL Configuration Query is not returning Domains without Groups

[petruki]

Describe the bug
For a given Domain without any Group element created, the GraphQL resource is failing to fetch
/adm-graphql when using with the following query:

{
    configuration(domain: "DOMAIN_ID") {
        domain {
            name
            activated
        }
        group {
            name
        }
    }
}

To Reproduce from Switcher Management
Steps to reproduce the behavior:

1. Create a new Domain
2. Select the domain created from the list
3. An error is thrown

Expected behavior
Display newly created Domain

Screenshots
Not applicable for SM v1.2.4 and API v1.2.4

Desktop (please complete the following information):

• OS: Windows 10
• Browser Firefox