[FEATURE] Support data_type property for KnnVectorProperty

[andrewrchen05]

Is your feature request related to a problem?

Binary vectors are supported but data_type is not a property for KnnVector

What solution would you like?

I want data_type to be supported in the KnnVectorProperty in the Java Client so I can call GetIndex to verify the data_type of an index https://javadoc.io/doc/org.opensearch.client/opensearch-java/latest/org/opensearch/client/opensearch/_types/mapping/KnnVectorProperty.html

                "vector": {
                    "type": "knn_vector",
                    "dimension": 1024,
                    "data_type": "binary",
                    "method": {
                        "engine": "faiss",
                        "space_type": "hamming",
                        "name": "hnsw",
                        "parameters": {}
                    }
                }

What alternatives have you considered?

Using generic client

Do you have any additional context?

Add any other context or screenshots about the feature request here.

[dblock]

I see it here in the API spec so codegen will pick it up with some more work.