### 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/DocumentParser.java
source.routing(),
            context.reorderParentAndGetDocs(),
            context.sourceToParse().source(),
            context.sourceToParse().getXContentType(),
            dynamicUpdate
        ) {
            @Override
            public String documentDescription() {
                IdFieldMapper idMapper = (IdFieldMapper) mappingLookup.getMapping().getMetadataMapperByName(IdFieldMapper.NAME);
                return idMapper.documentDescription(this);
            }
        };
    }
    private static void internalParseDocument(MetadataFieldMapper[] metadataFieldsMappers, DocumentParserContext context) {
        try {
            final boolean emptyDoc = isEmptyDoc(context.root(), context.parser());
            for (MetadataFieldMapper metadataMapper : metadataFieldsMappers) {
                metadataMapper.preParse(context);
            }
            if (context.root().isEnabled() == false) {
                
                context.parser().skipChildren();
            } else if (emptyDoc == false) {
                parseObjectOrNested(context);
            }
            executeIndexTimeScripts(context);
            for (MetadataFieldMapper metadataMapper : metadataFieldsMappers) {
                metadataMapper.postParse(context);
            }
        } catch (Exception e) {