KafkaSinkCluster - improve metadata response rewriting

[rukai]

Previously we were exposing internal cluster BrokerId's to the client.
However these need to be rewritten to the BrokerId's used by the shotover instances.
This PR introduces the required message rewriting logic.

The isr_nodes (in-sync-replica nodes) can follow the same logic as replica_nodes, so the logic is just copied over from there.

[codspeed-hq]

CodSpeed Performance Report

Merging #1740 will not alter performance

_{Comparing rukai:improve_metadata_rewriting (5100e5e) with main (0d50ddd)}

Summary

✅ 39 untouched benchmarks