### CI Link

https://gradle-enterprise.elastic.co/s/oyi6h23yl6k3o/tests/:x-pack:qa:full-cluster-restart:v8.11.0%23bwcTest/org.elasticsearch.xpack.restart.CoreFullClusterRestartIT/testClusterState%20%7Bcluster=OLD%7D

### Repro line

./gradlew ':qa:full-cluster-restart:v8.11.0#bwcTest' -Dtests.class="org.elasticsearch.upgrades.FullClusterRestartIT"

### Does it reproduce?

Yes

### Applicable branches

main

### Failure history

_No response_

### Failure excerpt

This test assumes that the index created version in cluster state matches the old node version.

That is no longer true due to the introduction of `IndexVersion`

https://github.com/elastic/elasticsearch/blob/52a6820813577abcb23191d862a01e32e652ed42/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/FullClusterRestartIT.java#L435-L440
qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/FullClusterRestartIT.java
}
            }""");
        Map<?, ?> longHistogram = entityAsMap(client().performRequest(longHistogramRequest));
        assertNoFailures(longHistogram);
        List<?> histoBuckets = (List<?>) XContentMapValues.extractValue("aggregations.histo.buckets", longHistogram);
        int histoCount = 0;
        for (Object entry : histoBuckets) {
            Map<?, ?> bucket = (Map<?, ?>) entry;
            histoCount += (Integer) bucket.get("doc_count");
        }
        assertTotalHits(histoCount, longHistogram);
        
        Request boolTermsRequest = new Request("GET", "/" + index + "/_search");
        boolTermsRequest.setJsonEntity("""
            {
              "aggs": {
                "bool_terms": {
                  "terms": {
                    "field": "bool"
                  }
                }
              }
            }""");
        Map<?, ?> boolTerms = entityAsMap(client().performRequest(boolTermsRequest));
        List<?> termsBuckets = (List<?>) XContentMapValues.extractValue("aggregations.bool_terms.buckets", boolTerms);
        int termsCount = 0;
        for (Object entry : termsBuckets) {
            Map<?, ?> bucket = (Map<?, ?>) entry;
            termsCount += (Integer) bucket.get("doc_count");
        }