Flaky test: ProducerTest.testWaitForExclusiveProducer

[example failure](https://github.com/apache/pulsar-client-cpp/actions/runs/3589998748/jobs/6042967481)

```
FAILED TESTS (1/376):
166 ms: ./pulsar-tests ProducerTest.testWaitForExclusiveProducer (try #1)
```

```
[ RUN ] ProducerTest.testWaitForExclusiveProducer
2022-12-01 06:25:37.989 INFO [140250769911488] ClientConnection:189 | [ -> pulsar://localhost:6650] Create ClientConnection, timeout=10000
2022-12-01 06:25:37.989 INFO [140250769911488] ConnectionPool:97 | Created connection for pulsar://localhost:6650
2022-12-01 06:25:37.991 INFO [140250766808640] ClientConnection:379 | [[::1]:37744 -> [::1]:6650] Connected to broker
2022-12-01 06:25:37.997 INFO [140250766808640] HandlerBase:72 | [persistent://public/default/testWaitForExclusiveProducer1669875937, p-name-1] Getting connection from pool
2022-12-01 06:25:38.038 INFO [140250766808640] ProducerImpl:190 | [persistent://public/default/testWaitForExclusiveProducer1669875937, p-name-1] Created producer on broker [[::1]:37744 -> [::1]:6650]
2022-12-01 06:25:38.043 INFO [140250769911488] ProducerImpl:721 | [persistent://public/default/testWaitForExclusiveProducer1669875937, p-name-1] Closing producer for topic persistent://public/default/testWaitForExclusiveProducer1669875937
2022-12-01 06:25:38.044 INFO [140250766808640] ProducerImpl:687 | [persistent://public/default/testWaitForExclusiveProducer1669875937, p-name-1] Closed producer 0
2022-12-01 06:25:38.045 INFO [140250766808640] HandlerBase:72 | [persistent://public/default/testWaitForExclusiveProducer1669875937, p-name-2] Getting connection from pool
2022-12-01 06:25:38.053 INFO [140250766808640] ProducerImpl:190 | [persistent://public/default/testWaitForExclusiveProducer1669875937, p-name-2] Created producer on broker [[::1]:37744 -> [::1]:6650]
/home/runner/work/pulsar-client-cpp/pulsar-client-cpp/tests/ProducerTest.cc:331: Failure
Expected equality of these values:
ResultOk
Which is: Ok
producer2.send(MessageBuilder().setContent("content").build())
Which is: ProducerNotInitialized
```

Beginne mit tests/ProducerTest.cc in Zeile 331 und führe ProducerTest.testWaitForExclusiveProducer aus, wobei der verknüpfte CI-Fehler als Ausgangspunkt dient. Verfolge die Initialisierung und die Sendesequenz von producer2, um festzustellen, warum der send ProducerNotInitialized beobachten kann. Die Aufgabe ist abgeschlossen, wenn der Test zuverlässig besteht und das Verhalten des exklusiven Producers erhalten bleibt.

Vom Indexierungsmodell aus dem Issue-Text verfasst.