### Elasticsearch Version

8.9.0

### Installed Plugins

_No response_

### Java Version

_bundled_

### OS Version

any

### Problem Description

If the context text supplied to the Question Answering task is longer than the model's `max_sequence_length` and `truncate` is set to `none` then inference on the model fails with the message:

```
status_exception: question answering result has invalid dimension, expected 2 found [6] 
```
<img width="1438" alt="Screenshot 2023-07-25 at 08 21 37" src="https://github.com/elastic/elasticsearch/assets/2353640/12d296f6-03b2-4cda-89ce-7399348c4104">


### Steps to Reproduce

Use long input text to the question answering task


### Work Aroundf
The fix is to truncate the context which unfortunately may remove the part of the document containing the answer. For reference the call is documented here

```
POST _ml/trained_models/distilbert-base-cased-distilled-squad/deployment/_infer
{
  "docs":[{ "text_field": "question answering context"}],
  "inference_config": {
    "question_answering": {
      "question": "The question to ask",
      "tokenization": {
        "bert": {
          "truncate": "second",
          "span": -1          
        }
      }
    }
  }
}
````

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/inference/nlp/tokenizers/TokenizationResult.java
int[] tokenIds,
        int[] tokenMap,
        int spanPrev,
        int sequenceId,
        int seqPairOffset
    ) {
        /**
         *
         * @param input The sequence inputs
         * @param tokens The delimited tokens (includes original text offsets)
         * @param truncated Was this tokenization truncated
         * @param tokenIds The token ids
         * @param tokenMap The token positions
         * @param spanPrev How many of the previous sub-sequence does this tokenization include
         * @param sequenceId A unique sequence ID to allow sub-sequence reconstitution
         * @param seqPairOffset if the tokenization is of a sequence pair, when does the second sequence start?
         *                      This does take into account separator token ids. Meaning, the offset will indicate the actual
         *                      start of the second sequence of the pair.
         */
        public Tokens {
            assert tokenIds.length == tokenMap.length;
            if (spanPrev != -1 && truncated) {
                throw new IllegalArgumentException("should not truncate when windowing is enabled");
            }
        }
        public OptionalInt getTokenIndex(int token) {
            return IntStream.range(0, tokenIds.length).filter(tokenIndex -> token == tokenIds[tokenIndex]).findFirst();
        }
    }
    interface TokensBuilder {