[fix][flaky-test] fix flaky test PerformanceTransactionTest (#18296)

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<!-- Either this PR fixes an issue, -->

Fixes #18282


### Modifications

We start 10 transactions and consume 50 messages in every transaction by default.

But notice `-r 10` set the consumption rate limit to be 10 msg per second, so every transaction is about 5 seconds.

In #17837 we set the transaction TTL to be 5 seconds, so transactions may be timeout randomly, which causes the test to fail.

To prove this, you can try to set `-r 9` or `-tto 4`, which will cause failure 100%.

So remove the `-r` option can fix this issue.

### Verifying this change

- [x] Make sure that the change passes the CI checks.

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### Matching PR in forked repository

PR in forked repository: labuladong#6

pulsar-testclient/src/test/java/org/apache/pulsar/testclient/PerformanceTransactionTest.java

@@ -163,7 +163,7 @@ public void testTxnPerf() throws Exception {
 
     @Test
     public void testProduceTxnMessage() throws InterruptedException, PulsarClientException {
-        String argString = "%s -r 10 -u %s -m %d -txn";
+        String argString = "%s -r 50 -u %s -m %d -txn";
         String topic = testTopic + UUID.randomUUID();
         int totalMessage = 100;
         String args = String.format(argString, topic, pulsar.getBrokerServiceUrl(), totalMessage);
@@ -174,14 +174,20 @@ public void testProduceTxnMessage() throws InterruptedException, PulsarClientExc
                 .subscribe();
         Thread thread = new Thread(() -> {
             try {
-                log.info("");
                 PerformanceProducer.main(args.split(" "));
             } catch (Exception e) {
                 e.printStackTrace();
             }
         });
         thread.start();
         thread.join();
+
+        Awaitility.await().untilAsserted(() -> {
+            admin.transactions().getCoordinatorStats().forEach((integer, transactionCoordinatorStats) -> {
+                Assert.assertEquals(transactionCoordinatorStats.ongoingTxnSize, 0);
+            });
+        });
+
         Consumer<byte[]> consumer = pulsarClient.newConsumer().subscriptionName("subName").topic(topic)
                 .subscriptionInitialPosition(SubscriptionInitialPosition.Earliest)
                 .subscriptionType(SubscriptionType.Exclusive)
@@ -198,7 +204,7 @@ public void testProduceTxnMessage() throws InterruptedException, PulsarClientExc
 
     @Test
     public void testConsumeTxnMessage() throws Exception {
-        String argString = "%s -r 10 -u %s -txn -ss %s -st %s -sp %s -ntxn %d -tto 5";
+        String argString = "%s -r 50 -u %s -txn -ss %s -st %s -sp %s -ntxn %d -tto 5";
         String subName = "sub";
         String topic = testTopic + UUID.randomUUID();
         String args = String.format(argString, topic, pulsar.getBrokerServiceUrl(), subName,