fix flaky test testUpdateDynamicLocalConfiguration (#11115)

When running test, it fails sporadically.

[example failure](https://github.com/apache/pulsar/pull/11114/checks?check_run_id=2921358630)
```
Error:  Tests run: 73, Failures: 1, Errors: 0, Skipped: 3, Time elapsed: 922.345 s <<< FAILURE! - in org.apache.pulsar.broker.admin.AdminApiTest
Error:  testUpdateDynamicLocalConfiguration(org.apache.pulsar.broker.admin.AdminApiTest)  Time elapsed: 10.05 s  <<< FAILURE!
org.awaitility.core.ConditionTimeoutException: Condition with lambda expression in org.apache.pulsar.broker.admin.AdminApiTest was not fulfilled within 10 seconds.
	at org.awaitility.core.ConditionAwaiter.await(ConditionAwaiter.java:165)
	at org.awaitility.core.CallableCondition.await(CallableCondition.java:78)
	at org.awaitility.core.CallableCondition.await(CallableCondition.java:26)
	at org.awaitility.core.ConditionFactory.until(ConditionFactory.java:895)
	at org.awaitility.core.ConditionFactory.until(ConditionFactory.java:864)
	at org.apache.pulsar.broker.admin.AdminApiTest.testUpdateDynamicLocalConfiguration(AdminApiTest.java:626)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:132)
	at org.testng.internal.InvokeMethodRunnable.runOne(InvokeMethodRunnable.java:45)
	at org.testng.internal.InvokeMethodRunnable.call(InvokeMethodRunnable.java:73)
	at org.testng.internal.InvokeMethodRunnable.call(InvokeMethodRunnable.java:11)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at java.base/java.lang.Thread.run(Thread.java:829)
```

1. simplify check logic and increase wait timeout to 30s.

(cherry picked from commit 9a66cbf)

pulsar-broker/src/test/java/org/apache/pulsar/broker/admin/AdminApiTest.java

@@ -615,23 +615,18 @@ public void testInvalidDynamicConfigContentInZK() throws Exception {
      *
      * @throws Exception
      */
-    @Test
+    @Test(timeOut = 30000)
     public void testUpdateDynamicLocalConfiguration() throws Exception {
         // (1) try to update dynamic field
         final long initValue = 30000;
         final long shutdownTime = 10;
         pulsar.getConfiguration().setBrokerShutdownTimeoutMs(initValue);
         // update configuration
         admin.brokers().updateDynamicConfiguration("brokerShutdownTimeoutMs", Long.toString(shutdownTime));
-        // sleep incrementally as zk-watch notification is async and may take some time
-        for (int i = 0; i < 5; i++) {
-            if (pulsar.getConfiguration().getBrokerShutdownTimeoutMs() == initValue) {
-                Thread.sleep(50 + (i * 10));
-            }
-        }
-
         // verify value is updated
-        assertEquals(pulsar.getConfiguration().getBrokerShutdownTimeoutMs(), shutdownTime);
+        Awaitility.waitAtMost(30, TimeUnit.SECONDS).untilAsserted(() -> {
+            assertEquals(pulsar.getConfiguration().getBrokerShutdownTimeoutMs(), shutdownTime);
+        });
     }
 
     @Test