### 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/DynamicFieldsBuilder.java
() -> strategy.newDynamicLongField(context, name)
                );
            } else if (numberType == XContentParser.NumberType.FLOAT
                || numberType == XContentParser.NumberType.DOUBLE
                || numberType == XContentParser.NumberType.BIG_DECIMAL) {
                    createDynamicField(
                        context,
                        name,
                        DynamicTemplate.XContentFieldType.DOUBLE,
                        () -> strategy.newDynamicDoubleField(context, name)
                    );
                } else {
                    throw new IllegalStateException("Unable to parse number of type [" + numberType + "]");
                }
        } else if (token == XContentParser.Token.VALUE_BOOLEAN) {
            createDynamicField(
                context,
                name,
                DynamicTemplate.XContentFieldType.BOOLEAN,
                () -> strategy.newDynamicBooleanField(context, name)
            );
        } else if (token == XContentParser.Token.VALUE_EMBEDDED_OBJECT) {
            
            createDynamicField(
                context,
                name,
                DynamicTemplate.XContentFieldType.BINARY,
                () -> CONCRETE.newDynamicBinaryField(context, name)
            );
        } else {