Utilize load balancing capabilities for BuildHooksWorker

Changelog: performance
MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/61905

app/workers/build_hooks_worker.rb

@@ -9,7 +9,7 @@ class BuildHooksWorker # rubocop:disable Scalability/IdempotentWorker
   queue_namespace :pipeline_hooks
   feature_category :continuous_integration
   urgency :high
-  data_consistency :delayed, feature_flag: :load_balancing_for_build_hooks_worker
+  data_consistency :delayed
   DATA_CONSISTENCY_DELAY = 3

config/feature_flags/development/load_balancing_for_build_hooks_worker.yml

----
-name: load_balancing_for_build_hooks_worker
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/57575
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/326095
-milestone: '13.11'
-type: development
-group: group::memory
-default_enabled: false

spec/workers/build_hooks_worker_spec.rb

@@ -45,6 +45,5 @@
   it_behaves_like 'worker with data consistency',
                   described_class,
-                  feature_flag: :load_balancing_for_build_hooks_worker,
                   data_consistency: :delayed
 end