Remove the FF skip_dag_manual_and_delayed_jobs

It has been enabled for a milestone

app/services/ci/process_build_service.rb

@@ -26,14 +26,6 @@ def enqueue(build)
     end
     def valid_statuses_for_build(build)
-      if ::Feature.enabled?(:skip_dag_manual_and_delayed_jobs, build.project, default_enabled: :yaml)
-        current_valid_statuses_for_build(build)
-      else
-        legacy_valid_statuses_for_build(build)
-      end
-    end
-
-    def current_valid_statuses_for_build(build)
       case build.when
       when 'on_success', 'manual', 'delayed'
         build.scheduling_type_dag? ? %w[success] : %w[success skipped]
@@ -45,23 +37,6 @@ def current_valid_statuses_for_build(build)
         []
       end
     end
-
-    def legacy_valid_statuses_for_build(build)
-      case build.when
-      when 'on_success'
-        build.scheduling_type_dag? ? %w[success] : %w[success skipped]
-      when 'on_failure'
-        %w[failed]
-      when 'always'
-        %w[success failed skipped]
-      when 'manual'
-        %w[success skipped]
-      when 'delayed'
-        %w[success skipped]
-      else
-        []
-      end
-    end
   end
 end

changelogs/unreleased/297240-remove-skip_dag_manual_and_delayed_jobs.yml

+---
+title: Remove the FF skip_dag_manual_and_delayed_jobs
+merge_request: 57086
+author:
+type: other

config/feature_flags/development/skip_dag_manual_and_delayed_jobs.yml

----
-name: skip_dag_manual_and_delayed_jobs
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/50765
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/297240
-milestone: '13.8'
-type: development
-group: group::pipeline authoring
-default_enabled: true

spec/services/ci/process_build_service_spec.rb

@@ -145,28 +145,5 @@
         expect { subject }.to change { build.status }.to(after_status)
       end
     end
-
-    context 'when FF skip_dag_manual_and_delayed_jobs is disabled on the project' do
-      let_it_be(:other_project) { create(:project) }
-
-      before do
-        stub_feature_flags(skip_dag_manual_and_delayed_jobs: other_project)
-      end
-
-      where(:build_when, :current_status, :after_status) do
-        :on_success | 'success' | 'pending'
-        :on_success | 'skipped' | 'skipped'
-        :manual     | 'success' | 'manual'
-        :manual     | 'skipped' | 'manual'
-        :delayed    | 'success' | 'manual'
-        :delayed    | 'skipped' | 'manual'
-      end
-
-      with_them do
-        it 'proceeds the build' do
-          expect { subject }.to change { build.status }.to(after_status)
-        end
-      end
-    end
   end
 end