### 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
Map<String, Object> responseBody = entityAsMap(client().performRequest(search));
                assertNoFailures(responseBody);
                int hits = extractTotalHits(responseBody);
                counts.add(hits);
            }
            assertEquals("All nodes should have a consistent number of documents", 1, counts.size());
        }
    }
    private int createTimeSeriesModeIndex(int replicas) throws IOException {
        XContentBuilder mappingsAndSettings = jsonBuilder();
        mappingsAndSettings.startObject();
        {
            mappingsAndSettings.startObject("settings");
            mappingsAndSettings.field("number_of_shards", 1);
            mappingsAndSettings.field("number_of_replicas", replicas);
            mappingsAndSettings.field("mode", "time_series");
            mappingsAndSettings.field("routing_path", "dim");
            mappingsAndSettings.field("time_series.start_time", 1L);
            mappingsAndSettings.field("time_series.end_time", DateUtils.MAX_MILLIS_BEFORE_9999 - 1);
            mappingsAndSettings.endObject();
        }
        {
            mappingsAndSettings.startObject("mappings");
            mappingsAndSettings.startObject("properties");
            {
                mappingsAndSettings.startObject("@timestamp").field("type", "date").endObject();
                mappingsAndSettings.startObject("dim").field("type", "keyword").field("time_series_dimension", true).endObject();
            }
            mappingsAndSettings.endObject();
            mappingsAndSettings.endObject();