Remove unused cluster name in environment. (#59605)

Removes an unused variable.

server/src/main/java/org/elasticsearch/env/Environment.java

@@ -19,7 +19,6 @@
 
 package org.elasticsearch.env;
 
-import org.elasticsearch.cluster.ClusterName;
 import org.elasticsearch.common.SuppressForbidden;
 import org.elasticsearch.common.io.PathUtils;
 import org.elasticsearch.common.settings.Setting;
@@ -113,7 +112,6 @@ public class Environment {
         pluginsFile = homeFile.resolve("plugins");
 
         List<String> dataPaths = PATH_DATA_SETTING.get(settings);
-        final ClusterName clusterName = ClusterName.CLUSTER_NAME_SETTING.get(settings);
         if (dataPaths.isEmpty() == false) {
             dataFiles = new Path[dataPaths.size()];
             for (int i = 0; i < dataPaths.size(); i++) {