Add missing shutdown call in test class (backport #695)

[mergify]

According to the API description of WaitForTopics https://docs.ros.org/en/rolling/p/launch_testing_ros/launch_testing_ros.wait_for_topics.html

In the other occurrences we had that already.

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This is an automatic backport of pull request #695 done by Mergify.

[mergify]

Cherry-pick of d6383fc has failed:

On branch mergify/bp/humble/pr-695
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	both modified:   example_11/test/test_carlikebot_launch.py

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[christophfroehlich]

see #699