Remove support for sidekiq-cluster's YAML files being arrays of strings
In !23771 (merged), we changed sidekiq-cluster to support both of the following in all_queues.yml
:
- An array of strings (queue names).
- An array of hashes (queues with name, feature category, resource boundary, etc.).
We're keeping 1 around for backwards compatibility which we can remove in 13.0.