[`Setting.versionSetting`](https://github.com/elastic/elasticsearch/blob/0652a5915586abbcdfdfffa91a391740f0147752/server/src/main/java/org/elasticsearch/common/settings/Setting.java#L1275) (only used by index compatibility setting) does not use the `Validator` passed in - its just discarded. Looks like it's been like this since it was introduced by https://github.com/elastic/elasticsearch/pull/83264 in 8.2.0.

Enabling this causes some tests to fail. Enabling this may cause problems for indexes that have a wonky setting already applied.
server/src/main/java/org/elasticsearch/common/settings/Setting.java
* storage.${backend}.enable=[true|false] can easily be added with this setting. Yet, affix key settings don't support updaters
     * out of the box unless {@link #getConcreteSetting(String)} is used to pull the updater.
     */
    public static <T> AffixSetting<T> affixKeySetting(
        String prefix,
        String suffix,
        Function<String, Setting<T>> delegateFactory,
        AffixSettingDependency... dependencies
    ) {
        BiFunction<String, String, Setting<T>> delegateFactoryWithNamespace = (ns, k) -> delegateFactory.apply(k);
        return affixKeySetting(new AffixKey(prefix, suffix), delegateFactoryWithNamespace, dependencies);
    }
    public static <T> AffixSetting<T> affixKeySetting(
        String prefix,
        String suffix,
        BiFunction<String, String, Setting<T>> delegateFactory,
        AffixSettingDependency... dependencies
    ) {
        Setting<T> delegate = delegateFactory.apply("_na_", "_na_");
        return new AffixSetting<>(new AffixKey(prefix, suffix), delegate, delegateFactory, dependencies);
    }
    private static <T> AffixSetting<T> affixKeySetting(
        AffixKey key,
        BiFunction<String, String, Setting<T>> delegateFactory,
        AffixSettingDependency... dependencies
    ) {
        Setting<T> delegate = delegateFactory.apply("_na_", "_na_");
        return new AffixSetting<>(key, delegate, delegateFactory, dependencies);
    }
    public interface Key {