### Description

Dynamic mappings can greatly help the getting started experience but they currently don't apply to all types, one example is `dense_vector`.

It's been suggested to automatically map float arrays as dense vectors when there are more than 100 values, or a heuristic along these lines.
server/src/main/java/org/elasticsearch/index/mapper/vectors/DenseVectorFieldMapper.java
};
            if (similarityThreshold != null) {
                knnQuery = new VectorSimilarityQuery(
                    knnQuery,
                    similarityThreshold,
                    similarity.score(similarityThreshold, elementType, dims)
                );
            }
            return knnQuery;
        }
        VectorSimilarity getSimilarity() {
            return similarity;
        }
        int getVectorDimensions() {
            return dims;
        }
        ElementType getElementType() {
            return elementType;
        }
    }
    private final ElementType elementType;
    private final int dims;
    private final boolean indexed;
    private final VectorSimilarity similarity;
    private final IndexOptions indexOptions;
    private final IndexVersion indexCreatedVersion;
    private DenseVectorFieldMapper(
        String simpleName,
        MappedFieldType mappedFieldType,
        ElementType elementType,