Remove client.type setting

The client.type setting is a holdover from the node client which was
removed in 8.0. The setting has been a noop since 8.0. This commit
removes the setting.

relates elastic#104574

server/src/main/java/org/elasticsearch/client/internal/Client.java

@@ -73,15 +73,7 @@
  * @see org.elasticsearch.node.Node#client()
  */
 public interface Client extends ElasticsearchClient {
-
-    // Note: This setting is registered only for bwc. The value is never read.
-    Setting<String> CLIENT_TYPE_SETTING_S = new Setting<>("client.type", "node", (s) -> {
-        return switch (s) {
-            case "node", "transport" -> s;
-            default -> throw new IllegalArgumentException("Can't parse [client.type] must be one of [node, transport]");
-        };
-    }, Property.NodeScope, Property.Deprecated);
-
+
     /**
      * The admin client that can be used to perform administrative operations.
      */

server/src/main/java/org/elasticsearch/common/settings/ClusterSettings.java

@@ -483,7 +483,6 @@ public void apply(Settings value, Settings current, Settings previous) {
         AutoCreateIndex.AUTO_CREATE_INDEX_SETTING,
         BaseRestHandler.MULTI_ALLOW_EXPLICIT_INDEX,
         ClusterName.CLUSTER_NAME_SETTING,
-        Client.CLIENT_TYPE_SETTING_S,
         ClusterModule.SHARDS_ALLOCATOR_TYPE_SETTING,
         EsExecutors.NODE_PROCESSORS_SETTING,
         ThreadContext.DEFAULT_HEADERS_SETTING,