KAFKA-8962; Use least loaded node for AdminClient#describeTopics (#7421)

Allow routing of `AdminClient#describeTopics` to any broker in the cluster than just the controller, so that we don't create a hotspot for this API call. `AdminClient#describeTopics` uses the broker's metadata cache which is asynchronously maintained, so routing to brokers other than the controller is not expected to have a significant difference in terms of metadata consistency; all metadata requests are eventually consistent.

This patch also fixes a few flaky test failures.

Reviewers: Ismael Juma <[email protected]>, José Armando García Sancio <[email protected]>, Jason Gustafson <[email protected]>

Author: dhruvilshah3

clients/src/main/java/org/apache/kafka/clients/admin/KafkaAdminClient.java

@@ -1537,7 +1537,7 @@ public DescribeTopicsResult describeTopics(final Collection<String> topicNames,
         }
         final long now = time.milliseconds();
         Call call = new Call("describeTopics", calcDeadlineMs(now, options.timeoutMs()),
-            new ControllerNodeProvider()) {
+            new LeastLoadedNodeProvider()) {
 
             private boolean supportsDisablingTopicCreation = true;
 

core/src/main/scala/kafka/controller/KafkaController.scala

@@ -790,7 +790,7 @@ class KafkaController(val config: KafkaConfig,
     electionType: ElectionType,
     electionTrigger: ElectionTrigger
   ): Map[TopicPartition, Either[Throwable, LeaderAndIsr]] = {
-    info(s"Starting replica leader election ($electionType) for partitions ${partitions.mkString(",")} triggerd by $electionTrigger")
+    info(s"Starting replica leader election ($electionType) for partitions ${partitions.mkString(",")} triggered by $electionTrigger")
     try {
       val strategy = electionType match {
         case ElectionType.PREFERRED => PreferredReplicaPartitionLeaderElectionStrategy