Backend: Remove deprecated worker BuildFinishedWorker

Replaced by ::Ci::BuildFinishedWorker

# frozen_string_literal: true

class BuildFinishedWorker < ::Ci::BuildFinishedWorker # rubocop:disable Scalability/IdempotentWorker
  # DEPRECATED: Not triggered since https://gitlab.com/gitlab-org/gitlab/-/merge_requests/64934/

  # We need to explicitly specify these settings. They aren't inheriting from the parent class.
  urgency :high
  worker_resource_boundary :cpu
end

Feature flag

The change in worker from BuildFinishedWorker to Ci::BuildFinishedWorker is behind a feature flag :ci_build_finished_worker_namespace_changed.

It is enabled on production, but still default false for self-managed. So we need to remove the feature flag and enable it before removing the worker

---
name: ci_build_finished_worker_namespace_changed
introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/64934
rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/335499
milestone: '14.1'
type: development
group: group::pipeline execution
default_enabled: false

https://dashboards.gitlab.net/d/sidekiq-worker-detail/sidekiq-worker-detail?orgId=1&var-PROMETHEUS_DS=Global&var-environment=gprd&var-stage=main&var-worker=BuildFinishedWorker&from=now-3h&to=now