fix test

Author: dao-jun

instrumentation/pulsar/pulsar-2.8/javaagent/src/test/java/io/opentelemetry/javaagent/instrumentation/pulsar/v2_8/PulsarClientTest.java

@@ -686,9 +686,9 @@ void testSendMessageWithTxn() throws Exception {
             .create();
     Transaction txn =
         client.newTransaction().withTransactionTimeout(5, TimeUnit.SECONDS).build().get();
+    testing.runWithSpan("parent1", () -> producer.newMessage(txn).value("test1").send());
     txn.commit();
 
-    testing.runWithSpan("parent1", () -> producer.newMessage(txn).value("test1").send());
     testing.waitAndAssertTraces(
         trace ->
             trace.hasSpansSatisfyingExactly(