### 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
assertTotalHits(termsCount, boolTerms);
    }
    void assertRealtimeGetWorks() throws IOException {
        Request disableAutoRefresh = new Request("PUT", "/" + index + "/_settings");
        disableAutoRefresh.setJsonEntity("""
            { "index": { "refresh_interval" : -1 }}""");
        client().performRequest(disableAutoRefresh);
        Request searchRequest = new Request("GET", "/" + index + "/_search");
        searchRequest.setJsonEntity("""
            { "query": { "match_all" : {} }}""");
        Map<?, ?> searchResponse = entityAsMap(client().performRequest(searchRequest));
        Map<?, ?> hit = (Map<?, ?>) ((List<?>) (XContentMapValues.extractValue("hits.hits", searchResponse))).get(0);
        String docId = (String) hit.get("_id");
        Request updateRequest = new Request("POST", "/" + index + "/_update/" + docId);
        updateRequest.setJsonEntity("""
            { "doc" : { "foo": "bar"}}""");
        client().performRequest(updateRequest);
        Request getRequest = new Request("GET", "/" + index + "/_doc/" + docId);
        Map<String, Object> getRsp = entityAsMap(client().performRequest(getRequest));
        Map<?, ?> source = (Map<?, ?>) getRsp.get("_source");
        assertTrue("doc does not contain 'foo' key: " + source, source.containsKey("foo"));
        Request enableAutoRefresh = new Request("PUT", "/" + index + "/_settings");
        enableAutoRefresh.setJsonEntity("""
            { "index": { "refresh_interval" : "1s" }}""");
        client().performRequest(enableAutoRefresh);
    }
    void assertStoredBinaryFields(int count) throws Exception {
        Request request = new Request("GET", "/" + index + "/_search");
        request.setJsonEntity("""
            {