Remove deprecated min_concurrency and max_concurrency for Sidekiq

What does this MR do?

Remove deprecated min_concurrency and max_concurrency option from Sidekiq which is replaced by the concurrency option.

Related issues

Removal issue: gitlab-com/gl-infra/scalability#3422

Deprecation mesage removal issue: #8491

Checklist

See Definition of done.

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Required

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Expected (please provide an explanation if not completing)

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