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
/*
 * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
 * or more contributor license agreements. Licensed under the Elastic License
 * 2.0; you may not use this file except in compliance with the Elastic License
 * 2.0.
 */
package org.elasticsearch.xpack.fleet;
import org.apache.http.util.EntityUtils;
import org.elasticsearch.client.Request;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.Response;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.util.concurrent.ThreadContext;
import org.elasticsearch.common.xcontent.XContentHelper;
import org.elasticsearch.test.SecuritySettingsSourceField;
import org.elasticsearch.test.rest.ESRestTestCase;
import org.elasticsearch.xcontent.XContentType;
import java.util.List;
import java.util.Map;
import static org.hamcrest.Matchers.containsString;
import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.not;
public class FleetSystemIndicesIT extends ESRestTestCase {