Enable sidekiq versioning

by removing feature flag

changelogs/unreleased/232934-sidekiq-versioning-flag.yml

+---
+title: Provide versioning support to Sidekiq workers
+merge_request: 39562
+author:
+type: other

config/feature_flags/development/sidekiq_versioning.yml

----
-name: sidekiq_versioning
-introduced_by_url: 
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/232934
-group: group::fulfillment
-type: development
-default_enabled: false
\ No newline at end of file

lib/gitlab/sidekiq_versioning/middleware.rb

@@ -4,7 +4,7 @@ module Gitlab
   module SidekiqVersioning
     class Middleware
       def call(worker, job, queue)
-        worker.job_version = job['version'] if worker.is_a?(ApplicationWorker) && Feature.enabled?(:sidekiq_versioning)
+        worker.job_version = job['version'] if worker.is_a?(ApplicationWorker)
 
         yield
       end

spec/lib/gitlab/sidekiq_versioning/middleware_spec.rb

@@ -44,17 +44,5 @@ RSpec.describe Gitlab::SidekiqVersioning::Middleware do
         expect { call! }.not_to raise_error
       end
     end
-
-    context 'when sidekiq_versioning is disabled' do
-      before do
-        stub_feature_flags(sidekiq_versioning: false)
-      end
-
-      it 'does not set job_version' do
-        expect(worker).not_to receive(:job_version=)
-
-        call!
-      end
-    end
   end
 end