MINOR: ConsumerNetworkClient does not need to send the remaining requests when the node is not ready (#6264)

Reviewers: Guozhang Wang <wangguoz@gmail.com>

clients/src/main/java/org/apache/kafka/clients/consumer/internals/ConsumerNetworkClient.java

@@ -474,6 +474,9 @@ public class ConsumerNetworkClient implements Closeable {
                 if (client.ready(node, now)) {
                     client.send(request, now);
                     iterator.remove();
+                } else {
+                    // try next node when current node is not ready
+                    break;
                 }
             }
         }