* Improve EC shards rebalancing logic across nodes.
- Favor target nodes with less preexisting shards, to ensure a fair distribution.
- Randomize selection when multiple possible target nodes are available.
- Add logic to account for replication settings when selecting target nodes (currently disabled).
* Fix minor test typo.
* Clarify internal error messages for `pickEcNodeToBalanceShardsInto()`.
Lisandro Pin