OpenSearch sync error on subOrganizationOf

[FuhuXia]

New error showed up during OpenSearch sync.

maybe it has something to do with the latest PR

• normalize DCAT values datagov-harvester#695

{'index': {'_index': 'datasets', '_id': '06a62c7f-56ea-4c7b-80a5-79412fdb0541', 'status': 400,
'error': {'type': 'mapper_parsing_exception', 'reason': 'object mapping for
[dcat.publisher.subOrganizationOf] tried to parse field [subOrganizationOf] as object,
but found a concrete value'}}}