Remove Unused AckClusterStatePublishResponseHandler (#39892)

This isn't used anywhere

server/src/main/java/org/elasticsearch/discovery/AckClusterStatePublishResponseHandler.java

@@ -1,75 +0,0 @@
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-package org.elasticsearch.discovery;
-
-import org.apache.logging.log4j.Logger;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.elasticsearch.cluster.node.DiscoveryNode;
-
-import java.util.Set;
-
-/**
- * Allows to wait for all nodes to reply to the publish of a new cluster state
- * and notifies the {@link org.elasticsearch.discovery.Discovery.AckListener}
- * so that the cluster state update can be acknowledged
- */
-public class AckClusterStatePublishResponseHandler extends BlockingClusterStatePublishResponseHandler {
-
-    private static final Logger logger = LogManager.getLogger(AckClusterStatePublishResponseHandler.class);
-
-    private final Discovery.AckListener ackListener;
-
-    /**
-     * Creates a new AckClusterStatePublishResponseHandler
-     * @param publishingToNodes the set of nodes to which the cluster state will be published and should respond
-     * @param ackListener the {@link org.elasticsearch.discovery.Discovery.AckListener} to notify for each response
-     *                    gotten from non master nodes
-     */
-    public AckClusterStatePublishResponseHandler(Set<DiscoveryNode> publishingToNodes, Discovery.AckListener ackListener) {
-        //Don't count the master as acknowledged, because it's not done yet
-        //otherwise we might end up with all the nodes but the master holding the latest cluster state
-        super(publishingToNodes);
-        this.ackListener = ackListener;
-    }
-
-    @Override
-    public void onResponse(DiscoveryNode node) {
-        super.onResponse(node);
-        onNodeAck(ackListener, node, null);
-    }
-
-    @Override
-    public void onFailure(DiscoveryNode node, Exception e) {
-        try {
-            super.onFailure(node, e);
-        } finally {
-            onNodeAck(ackListener, node, e);
-        }
-    }
-
-    private void onNodeAck(final Discovery.AckListener ackListener, DiscoveryNode node, Exception e) {
-        try {
-            ackListener.onNodeAck(node, e);
-        } catch (Exception inner) {
-            inner.addSuppressed(e);
-            logger.debug(() -> new ParameterizedMessage("error while processing ack for node [{}]", node), inner);
-        }
-    }
-}