Flaky-test: BrokerServiceLookupTest.testLookupConnectionNotCloseIfGetUnloadingExOrMetadataEx

### Search before asking

- [X] I searched in the [issues](https://github.com/apache/pulsar/issues) and found nothing similar.

### Example failures

- [2023-09-27T08:17:07.8103784Z](https://github.com/apache/pulsar/actions/runs/6323018541/job/17170129652#step:10:788)

### Exception stacktrace

```
java.lang.AssertionError: expected [true] but found [false]
at org.testng.Assert.fail(Assert.java:110)
at org.testng.Assert.failNotEquals(Assert.java:1577)
at org.testng.Assert.assertTrue(Assert.java:56)
at org.testng.Assert.assertTrue(Assert.java:66)
at org.apache.pulsar.client.api.BrokerServiceLookupTest.testLookupConnectionNotCloseIfGetUnloadingExOrMetadataEx(BrokerServiceLookupTest.java:1162)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:568)
at org.testng.internal.invokers.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:139)
at org.testng.internal.invokers.InvokeMethodRunnable.runOne(InvokeMethodRunnable.java:47)
at org.testng.internal.invokers.InvokeMethodRunnable.call(InvokeMethodRunnable.java:76)
at org.testng.internal.invokers.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:1136)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
at java.base/java.lang.Thread.run(Thread.java:833)

```

### Are you willing to submit a PR?

- [ ] I'm willing to submit a PR!