### Elasticsearch Version

main

### Installed Plugins

_No response_

### Java Version

_bundled_

### OS Version

Darwin

### Problem Description

Sorting fails sometimes with the error

```
No TopN sorting encoder for type UNSUPPORTED
```


### Steps to Reproduce

Playing with ES|QL I tried to run the following query

`from logstash-* | sort extension.keyword`

This returns the error

```
No TopN sorting encoder for type UNSUPPORTED
```

If I run the query:

`from logstash-*  | keep extension.keyword | sort extension.keyword`

the data return successfully.

### Logs (if relevant)

_No response_
x-pack/plugin/esql/compute/src/main/java/org/elasticsearch/compute/operator/topn/DefaultSortableTopNEncoder.java
@Override
    public int encodeBytesRef(BytesRef value, BreakingBytesRefBuilder bytesRefBuilder) {
        throw new IllegalStateException("Cannot find encoder for BytesRef value");
    }
    @Override
    public BytesRef decodeBytesRef(BytesRef bytes, BytesRef scratch) {
        throw new IllegalStateException("Cannot find encoder for BytesRef value");
    }
    @Override
    public String toString() {
        return "DefaultUnsortable";
    }
    @Override
    public TopNEncoder toSortable() {
        return this;
    }
    @Override
    public TopNEncoder toUnsortable() {
        return TopNEncoder.DEFAULT_UNSORTABLE;
    }
}