Update spatial handling for DCAT-US v3.0 Location object #6040

What: DCAT-US v3.0 spatial is a Location object, not a plain string. The current translate_spatial and translate_spatial_to_geojson utilities produce GeoJSON strings or dicts. These need to handle the v3.0 Location object as both input (when reading a v3.0 record) and output (when producing a v3.0-compatible record from ISO or v1.1 source).

Likely scope:

• Update translate_spatial to accept a Location object dict as input and extract the geometry value from it for processing
• Update or wrap translate_spatial_to_geojson to produce a Location object dict as output when the target schema is v3.0
• Ensure the translated_spatial column in the dataset table stores the GeoJSON geometry (extracted from the Location object) for OpenSearch indexing
• Update _dataset_payload in Record to produce the correct spatial structure based on the source schema_type

Done When:

• v3.0 records with Location object spatial pass validation and store correctly
• v1.1 records with plain string spatial continue to work
• ISO records (which arrive via MDTranslator as v1.1 output) continue to work
• OpenSearch spatial indexing is unaffected

Notes:

• The DCAT-US v3.0 Location class definition is at github.com/GSA/dcat-us/blob/main/jsonschema/definitions/Location.json
• Do not change the internal GeoJSON representation used for OpenSearch -- only the DCAT-facing structure needs to change