Part of https://github.com/elastic/kibana/issues/153483

We have identified a problem with the index template/ILM policy structure so we need to stop the ILM policy from rolling over while we get a long term fix.

In investigating this I also noticed that the index templates do not set `hidden` to be true which they should.


x-pack/plugin/fleet/src/javaRestTest/java/org/elasticsearch/xpack/fleet/FleetSystemIndicesIT.java
static final String BASIC_AUTH_VALUE = basicAuthHeaderValue(
        "x_pack_rest_user",
        SecuritySettingsSourceField.TEST_PASSWORD_SECURE_STRING
    );
    @Override
    protected Settings restClientSettings() {
        return Settings.builder()
            .put(ThreadContext.PREFIX + ".Authorization", BASIC_AUTH_VALUE)
            .put(ThreadContext.PREFIX + ".X-elastic-product-origin", "fleet")
            .build();
    }
    private void expectSystemIndexWarning(Request request, String indexName) {
        String warningMsg = "index name ["