Add a dev FF for payment validation

The payment validation will be performed via CustomersDot API.

config/feature_flags/development/use_api_for_payment_validation.yml

+---
+name: use_api_for_payment_validation
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/84292
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/357282
+milestone: '14.10'
+type: development
+group: group::purchase
+default_enabled: false

ee/app/controllers/ee/projects/pipelines_controller.rb

@@ -14,6 +14,7 @@ module EE
           push_frontend_feature_flag(:secure_vulnerability_training, project, default_enabled: :yaml)
           push_frontend_feature_flag(:vulnerability_report_pagination, current_user, default_enabled: :yaml)
           push_frontend_feature_flag(:vulnerability_report_page_size_selector, default_enabled: :yaml)
+          push_frontend_feature_flag(:use_api_for_payment_validation, project, default_enabled: :yaml)
         end
 
         feature_category :license_compliance, [:licenses]

ee/spec/features/projects/pipelines/pipeline_spec.rb

@@ -332,6 +332,7 @@ RSpec.describe 'Pipeline', :js do
 
     before do
       allow(Gitlab).to receive(:com?) { true }
+      stub_feature_flags(account_verification_payment_form_refresh: false)
       create(:gitlab_subscription, :active_trial, namespace: namespace, hosted_plan: ultimate_plan)
     end
 
@@ -349,6 +350,14 @@ RSpec.describe 'Pipeline', :js do
       visit current_path
       expect(page).not_to have_selector("#credit-card-verification-modal")
     end
+
+    context 'with payment validation via api feature flag' do
+      it 'pushes use_api_for_payment_validation feature flag' do
+        visit project_pipeline_validate_account_path(project, pipeline)
+
+        expect(page).to have_pushed_frontend_feature_flags(useApiForPaymentValidation: true)
+      end
+    end
   end
 
   private