### 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
"query": {
                "match_all": {}
              },
              "size": 100,
              "stored_fields": "binary"
            }""");
        Map<String, Object> rsp = entityAsMap(client().performRequest(request));
        assertTotalHits(count, rsp);
        List<?> hits = (List<?>) XContentMapValues.extractValue("hits.hits", rsp);
        assertEquals(100, hits.size());
        for (Object hit : hits) {
            Map<?, ?> hitRsp = (Map<?, ?>) hit;
            List<?> values = (List<?>) XContentMapValues.extractValue("fields.binary", hitRsp);
            assertEquals(1, values.size());
            String value = (String) values.get(0);
            byte[] binaryValue = Base64.getDecoder().decode(value);
            assertEquals("Unexpected string length [" + value + "]", 16, binaryValue.length);
        }
    }
    static String toStr(Response response) throws IOException {
        return EntityUtils.toString(response.getEntity());
    }
    static void assertNoFailures(Map<?, ?> response) {
        int failed = (int) XContentMapValues.extractValue("_shards.failed", response);
        assertEquals(0, failed);
    }
    void assertTotalHits(int expectedTotalHits, Map<?, ?> response) {
        int actualTotalHits = extractTotalHits(response);
        assertEquals(response.toString(), expectedTotalHits, actualTotalHits);
    }