[BEAM-7378] Fix Python PVR tests by adding a Kafka client dependency
[BEAM-7378] Fix Python PVR tests by adding a Kafka client dependency

The Expansion Server is started with the Flink Job Server and needs to have a
Kafka client to correctly expand transforms. The Kafka module was recently
changed to not bundle a Kafka client.

markflyhigh/incubator-beam,chamikaramj/beam,apache/beam,apache/beam,RyanSkraba/beam,markflyhigh/incubator-beam,lukecwik/incubator-beam,lukecwik/incubator-beam,apache/beam,robertwb/incubator-beam,robertwb/incubator-beam,lukecwik/incubator-beam,markflyhigh/incubator-beam,iemejia/incubator-beam,apache/beam,lukecwik/incubator-beam,RyanSkraba/beam,RyanSkraba/beam,chamikaramj/beam,lukecwik/incubator-beam,apache/beam,robertwb/incubator-beam,apache/beam,RyanSkraba/beam,robertwb/incubator-beam,markflyhigh/incubator-beam,lukecwik/incubator-beam,robertwb/incubator-beam,iemejia/incubator-beam,RyanSkraba/beam,lukecwik/incubator-beam,lukecwik/incubator-beam,RyanSkraba/beam,markflyhigh/incubator-beam,apache/beam,markflyhigh/incubator-beam,lukecwik/incubator-beam,robertwb/incubator-beam,apache/beam,robertwb/incubator-beam,chamikaramj/beam,chamikaramj/beam,chamikaramj/beam,robertwb/incubator-beam,markflyhigh/incubator-beam,apache/beam,robertwb/incubator-beam,apache/beam,lukecwik/incubator-beam,apache/beam,robertwb/incubator-beam,chamikaramj/beam,RyanSkraba/beam,chamikaramj/beam,chamikaramj/beam,chamikaramj/beam,chamikaramj/beam