Cannot import contributors when at least one role is provided

[bryan-brancotte]

With the following json, no contributors are imported, while when removing the one role specified the two contributors are imported.

2 contributors 1 role => none imported

{
    "@context": "https://w3id.org/codemeta/3.0",
    "type": "SoftwareSourceCode",
    "contributor": [
        {
            "id": "http://orcid.org/0000-0002-1825-0097",
            "type": "Person",
            "affiliation": {
                "type": "Organization",
                "name": "Department of Computer Science, University of Pisa"
            },
            "email": "jane.doe@example.org",
            "familyName": "Doe",
            "givenName": "Jane"
        },
        {
            "id": "http://orcid.org/0000-0002-1825-0098",
            "type": "Person",
            "affiliation": {
                "type": "Organization",
                "name": "Department of Computer Science, University of Pisa"
            },
            "email": "john.doe@example.org",
            "familyName": "Doe",
            "givenName": "John"
        },
        {
            "type": "Role",
            "contributor": "http://orcid.org/0000-0002-1825-0098",
            "roleName": "Dev"
        }
    ],
    "name": "Foo bar"
}

2 contributors 0 role => 2 imported

{
    "@context": "https://w3id.org/codemeta/3.0",
    "type": "SoftwareSourceCode",
    "contributor": [
        {
            "id": "http://orcid.org/0000-0002-1825-0097",
            "type": "Person",
            "affiliation": {
                "type": "Organization",
                "name": "Department of Computer Science, University of Pisa"
            },
            "email": "jane.doe@example.org",
            "familyName": "Doe",
            "givenName": "Jane"
        },
        {
            "id": "http://orcid.org/0000-0002-1825-0098",
            "type": "Person",
            "affiliation": {
                "type": "Organization",
                "name": "Department of Computer Science, University of Pisa"
            },
            "email": "john.doe@example.org",
            "familyName": "Doe",
            "givenName": "John"
        }
    ],
    "name": "Foo bar"
}