KafkaSinkCluster: route ListGroups request

[rukai]

This turned out to be more complicated than I initially thought.

When AdminClient.listConsumerGroups is called, the java driver sends a ListGroups request to all brokers and then combines the responses, removing any duplicate entries.

To ensure that all groups are included shotover should also send requests to all brokers and combine them.
However we should avoid sending requests outside of shotovers rack to reduce the load of the operation.
This should still include all the results as the client will query all shotover nodes, and each shotover node will query a portion of the kafka brokers, ensuring all kafka nodes are queried.

A second commit was added to avoid running the new test case in the tests with a down shotover node, since that resulted in test failures as the down shotover node can not report its racks groups.
It might be easier to review that commit separately from the main commit.

[codspeed-hq]

CodSpeed Performance Report

Merging #1790 will not alter performance

_{Comparing rukai:split_list_groups (03d1477) with main (e3bac43)}

Summary

✅ 38 untouched benchmarks