[fix][test] Add reconsumeLater call in RetryTopicTest#testRetryTopicWithMultiTopic.

[thetumbled]

Motivation

org.apache.pulsar.client.api.RetryTopicTest#testRetryTopicWithMultiTopic don't test the behavior of retry topic at all.
Instead of calling reconsumeLater to trigger redelivery, current test code trigger redelivery base on ack timeout.

Modifications

Add reconsumeLater call to test the behavior of retry topic with multiple topics.

Verifying this change

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This change is a trivial rework / code cleanup without any test coverage.

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• Dependencies (add or upgrade a dependency)
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• Anything that affects deployment

Documentation

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Matching PR in forked repository

PR in forked repository:

[nodece]

LGTM

BTW, DO NOT add the blank between [type] and [scope].