Changes to Get Document Indexing Status

the response property data/items/cleaning_completed_at became nullable for the status 200

the response property data/items/completed_at became nullable for the status 200

the response property data/items/parsing_completed_at became nullable for the status 200

the response property data/items/processing_started_at became nullable for the status 200

the response property data/items/splitting_completed_at became nullable for the status 200