### Elasticsearch Version

main

### Installed Plugins

_No response_

### Java Version

_bundled_

### OS Version

all

### Problem Description

Do this

### Steps to Reproduce

```
rm /tmp/evil
for a in {0..9}; do
   for b in {0..9}; do
      echo '{"index": {}}' >> /tmp/evil
      echo '{"a": '$a', "b": '$b'}' >> /tmp/evil
   done
done
echo >> /tmp/evil

curl -uelastic:password -XDELETE localhost:9200/test
curl -HContent-Type:application/json -uelastic:password -XPUT localhost:9200/test
curl -HContent-Type:application/json -uelastic:password -XPOST localhost:9200/test/_bulk --data-binary @/tmp/evil
curl -HContent-Type:application/json -uelastic:password -XPOST localhost:9200/test/_forcemerge?max_num_segments=1
curl -HContent-Type:application/json -uelastic:password -XPOST localhost:9200/test/_refresh

curl -HContent-Type:application/json -uelastic:password -XPOST localhost:9200/_esql?pretty -d'{
   "query": "FROM test | STATS MAX(a) BY a, b | KEEP a"
}'
```

### Logs (if relevant)

_No response_
x-pack/plugin/esql/qa/testFixtures/src/main/java/org/elasticsearch/xpack/esql/CsvTestUtils.java
LOOKUP.put("D", DOUBLE);
            LOOKUP.put("K", KEYWORD);
            LOOKUP.put("S", KEYWORD);
            LOOKUP.put("STRING", KEYWORD);
            LOOKUP.put("TXT", TEXT);
            LOOKUP.put("N", NULL);
            LOOKUP.put("DATE", DATETIME);
            LOOKUP.put("DT", DATETIME);
            LOOKUP.put("V", VERSION);
        }
        private final Function<String, Object> converter;
        private final Class<?> clazz;
        private final Comparator<Object> comparator;
        @SuppressWarnings("unchecked")
        Type(Function<String, Object> converter, Class<?> clazz) {
            this(
                converter,
                Comparable.class.isAssignableFrom(clazz) ? (a, b) -> ((Comparable) a).compareTo(b) : Comparator.comparing(Object::toString),
                clazz
            );
        }
        Type(Function<String, Object> converter, Comparator<Object> comparator, Class<?> clazz) {
            this.converter = converter;
            this.comparator = comparator;
            this.clazz = clazz;
        }
        public static Type asType(String name) {
            return LOOKUP.get(name.toUpperCase(Locale.ROOT));
        }
        public static Type asType(ElementType elementType) {