### 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
*  <li>Write some documents to the write alias
     *  <li>Roll over the index
     *  <li>Make sure the document count is correct
     *  <li>Upgrade
     *  <li>Write some more documents to the write alias
     *  <li>Make sure the document count is correct
     * </ol>
     */
    public void testRollover() throws IOException {
        if (isRunningAgainstOldCluster()) {
            Request createIndex = new Request("PUT", "/" + index + "-000001");
            createIndex.setJsonEntity(Strings.format("""
                {
                  "aliases": {
                    "%s_write": {}
                  }
                }""", index));
            client().performRequest(createIndex);
        }
        int bulkCount = 10;
        String bulk = """
            {"index":{}}
            {"test":"test"}
            """.repeat(bulkCount);
        Request bulkRequest = new Request("POST", "/" + index + "_write/_bulk");
        bulkRequest.setJsonEntity(bulk);
        bulkRequest.addParameter("refresh", "");
        assertThat(EntityUtils.toString(client().performRequest(bulkRequest).getEntity()), containsString("\"errors\":false"));
        if (isRunningAgainstOldCluster()) {
            Request rolloverRequest = new Request("POST", "/" + index + "_write/_rollover");