Bugfix: Match on subscribe_to_topics success to avoid getting stuck

[rodrigues]

In case the kafka cluster is temporarily unavailable, when subscribe_to_topics retries are exhausted, it simply exits the function without crashing.

When kafka cluster is back, if that happened after client_down_retry_expire, it won't subscribe to topics, and the consumer gets stuck.

With this change, it will crash after retries are exhausted and topic subscription didn't complete successfully, restarting properly as expected.