### 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
}
        }
    }
    /**
     * Tests snapshot/restore by creating a snapshot and restoring it. It takes
     * a snapshot on the old cluster and restores it on the old cluster as a
     * sanity check and on the new cluster as an upgrade test. It also takes a
     * snapshot on the new cluster and restores that on the new cluster as a
     * test that the repository is ok with containing snapshot from both the
     * old and new versions. All of the snapshots include an index, a template,
     * and some routing configuration.
     */
    public void testSnapshotRestore() throws IOException {
        int count;
        if (isRunningAgainstOldCluster()) {
            
            count = between(200, 300);
            Settings.Builder settings = Settings.builder();
            if (minimumNodeVersion().before(Version.V_8_0_0) && randomBoolean()) {
                settings.put(IndexSettings.INDEX_SOFT_DELETES_SETTING.getKey(), randomBoolean());
            }
            createIndex(index, settings.build());
            indexRandomDocuments(count, true, true, randomBoolean(), i -> jsonBuilder().startObject().field("field", "value").endObject());
        } else {
            count = countOfIndexedRandomDocuments();
        }
        
        refreshAllIndices();
        
        Request countRequest = new Request("GET", "/" + index + "/_search");