mappings: multiple locations with geometry fail indexing

[slint]

To reproduce, try to create a draft via the REST API with the following metadata:

data = {
    "metadata": {
        ...
        "locations": {
            "features": [
                {"geometry": {"type": "Point", "coordinates": [10.2, 5.0]}},
                {"geometry": {"type": "Point", "coordinates": [5.1, 1.23]}},
            ]
        }
    }
}

Will raise the following error from OpenSearch:

{'error': {'reason': 'DocValuesField "metadata.locations.features.geometry" '
                     'appears more than once in this document (only one value '
                     'is allowed per field)',
           'root_cause': [{'reason': 'DocValuesField '
                                     '"metadata.locations.features.geometry" '
                                     'appears more than once in this document '
                                     '(only one value is allowed per field)',
                           'type': 'illegal_argument_exception'}],
           'type': 'illegal_argument_exception'},
 'status': 400}

Seems to be related to opensearch-project/OpenSearch#10958, which in theory has been fixed, so probably needs further investigation.