### 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/test/java/org/elasticsearch/index/mapper/vectors/DenseVectorFieldMapperTests.java
b.field("index", indexed);
        }
        if (indexed) {
            b.field("similarity", "dot_product");
            if (indexOptionsSet) {
                b.startObject("index_options");
                b.field("type", "hnsw");
                b.field("m", 5);
                b.field("ef_construction", 50);
                b.endObject();
            }
        }
    }
    @Override
    protected Object getSampleValueForDocument() {
        return elementType == ElementType.BYTE ? List.of((byte) 1, (byte) 1, (byte) 1, (byte) 1) : List.of(0.5, 0.5, 0.5, 0.5);
    }
    @Override
    protected void registerParameters(ParameterChecker checker) throws IOException {
        checker.registerConflictCheck(
            "dims",
            fieldMapping(b -> b.field("type", "dense_vector").field("dims", 4)),
            fieldMapping(b -> b.field("type", "dense_vector").field("dims", 5))
        );
        checker.registerConflictCheck(
            "similarity",
            fieldMapping(b -> b.field("type", "dense_vector").field("dims", 4).field("index", true).field("similarity", "dot_product")),
            fieldMapping(b -> b.field("type", "dense_vector").field("dims", 4).field("index", true).field("similarity", "l2_norm"))
        );