EmbeddedKafka.consumeFromAnEmbeddedTopic should wait for partitions to be assigned

[elliotkennedy]

I think there is a bug in EmbeddedKafka.consumeFromAnEmbeddedTopic(Consumer consumer, String topic)

. It does not wait to be assigned partitions from the embedded topic as is the case with EmbeddedKafka.onsumeFromAllEmbeddedTopics(Consumer consumer).

I created a test, which fails with the current behaviour here.

When a consumer is created with EmbeddedKafka.consumeFromAllEmbeddedTopics(Consumer consumer), all the messages are received.

When a consumer is created with EmbeddedKafka.consumeFromAnEmbeddedTopic(Consumer consumer, String topic), the messages are not all received.

I created a PR here if you agree with this.