### 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/src/main/java/org/elasticsearch/xpack/esql/action/EsqlQueryResponse.java
.positionToXContent(page.getBlock(column), scratch);
                            return Iterators.forRange(
                                0,
                                page.getPositionCount(),
                                position -> (builder, params) -> toXContent.positionToXContent(builder, params, position)
                            );
                        }),
                        ChunkedToXContentHelper.endArray()
                    )
                ),
                Function.identity()
            );
        } else {
            valuesIt = Iterators.flatMap(pages.iterator(), page -> {
                final int columnCount = columns.size();
                assert page.getBlockCount() == columnCount;
                final ColumnInfo.PositionToXContent[] toXContents = new ColumnInfo.PositionToXContent[columnCount];
                for (int column = 0; column < columnCount; column++) {
                    toXContents[column] = columns.get(column).positionToXContent(page.getBlock(column), scratch);
                }
                return Iterators.forRange(0, page.getPositionCount(), position -> (builder, params) -> {
                    builder.startArray();
                    for (int c = 0; c < columnCount; c++) {
                        toXContents[c].positionToXContent(builder, params, position);
                    }
                    return builder.endArray();
                });
            });
        }
        return Iterators.concat(ChunkedToXContentHelper.startObject(), ChunkedToXContentHelper.singleChunk((builder, params) -> {