### 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
mappingsAndSettings.endObject();
                }
                mappingsAndSettings.endObject();
                mappingsAndSettings.startObject("settings");
                {
                    mappingsAndSettings.field("index.number_of_shards", 5);
                }
                mappingsAndSettings.endObject();
            }
            mappingsAndSettings.endObject();
            Request createIndex = new Request("PUT", "/" + index);
            createIndex.setJsonEntity(Strings.toString(mappingsAndSettings));
            client().performRequest(createIndex);
            numDocs = randomIntBetween(512, 1024);
            indexRandomDocuments(
                numDocs,
                true,
                true,
                randomBoolean(),
                i -> JsonXContent.contentBuilder().startObject().field("field", "value").endObject()
            );
            ensureGreen(index); 
            Request updateSettingsRequest = new Request("PUT", "/" + index + "/_settings");
            updateSettingsRequest.setJsonEntity("{\"settings\": {\"index.blocks.write\": true}}");
            client().performRequest(updateSettingsRequest);
            Request shrinkIndexRequest = new Request("PUT", "/" + index + "/_shrink/" + shrunkenIndex);
            shrinkIndexRequest.setJsonEntity("{\"settings\": {\"index.number_of_shards\": 1}}");
            client().performRequest(shrinkIndexRequest);
            refreshAllIndices();
        } else {