### 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
server/src/main/java/org/elasticsearch/index/IndexVersion.java
private static final IndexVersion CURRENT = findCurrent(V_8_10_0);
        
        private static IndexVersion findCurrent(IndexVersion fallback) {
            var versionExtension = VersionExtension.load();
            if (versionExtension == null) {
                return fallback;
            }
            var version = versionExtension.getCurrentIndexVersion();
            assert version.onOrAfter(fallback);
            assert version.luceneVersion.equals(Version.LATEST)
                : "IndexVersion must be upgraded to ["
                + Version.LATEST
                + "] is still set to ["
                + version.luceneVersion
                + "]";
            return version;