### Description

We've been working on the health API for a while and the breaking changes have slowed to the point where we can promote the API away from the `/_internal` categorization.
qa/smoke-test-http/src/javaRestTest/java/org/elasticsearch/http/HealthRestCancellationIT.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 and the Server Side Public License, v 1; you may not use this file except
 * in compliance with, at your election, the Elastic License 2.0 or the Server
 * Side Public License, v 1.
 */
package org.elasticsearch.http;
import org.apache.http.client.methods.HttpGet;
import org.elasticsearch.action.support.PlainActionFuture;
import org.elasticsearch.client.Cancellable;
import org.elasticsearch.client.Request;
import org.elasticsearch.client.Response;
import org.elasticsearch.common.util.CollectionUtils;
import org.elasticsearch.core.Releasable;
import org.elasticsearch.core.Releasables;
import org.elasticsearch.health.GetHealthAction;
import org.elasticsearch.health.HealthIndicatorResult;
import org.elasticsearch.health.HealthIndicatorService;
import org.elasticsearch.health.HealthStatus;
import org.elasticsearch.health.SimpleHealthIndicatorDetails;