Flaky-test: BrokerServiceTest.testLookupThrottlingForClientByClient

```
Error: Tests run: 44, Failures: 1, Errors: 0, Skipped: 31, Time elapsed: 116.962 s <<< FAILURE! - in org.apache.pulsar.broker.service.BrokerServiceTest
Error: testLookupThrottlingForClientByClient(org.apache.pulsar.broker.service.BrokerServiceTest) Time elapsed: 0.482 s <<< FAILURE!
java.lang.AssertionError: At least one should fail
at org.testng.Assert.fail(Assert.java:99)
at org.apache.pulsar.broker.service.BrokerServiceTest.testLookupThrottlingForClientByClient(BrokerServiceTest.java:1065)
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.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:1136)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
at java.base/java.lang.Thread.run(Thread.java:833)
```
[example failure](https://github.com/apache/pulsar/runs/7277547968?check_suite_focus=true)

Start with BrokerServiceTest.java and testLookupThrottlingForClientByClient at line 1065, then run the test repeatedly to reproduce the intermittent assertion failure. Trace the lookup-throttling behavior involved in the test; done means the test reliably observes a throttled request without flaky failures.

Written by the indexing model from the issue text.