Update passed namespace id

Selected group should correspond to the namespace id

ee/app/assets/javascripts/vue_shared/purchase_flow/components/checkout/confirm_order.vue

@@ -37,7 +37,7 @@ export default {
         const { customer } = data;
         return {
           setup_for_company: data.isSetupForCompany,
-          selected_group: data.subscription.namespaceId,
+          selected_group: data.selectedNamespaceId,
           new_user: data.isNewUser,
           redirect_after_success: data.redirectAfterSuccess,
           customer: {

ee/spec/frontend/subscriptions/buy_minutes/components/checkout/confirm_order_spec.js

@@ -76,7 +76,7 @@ describe('Confirm Order', () => {
         expect(Api.confirmOrder).toHaveBeenCalledTimes(1);
         expect(Api.confirmOrder.mock.calls[0][0]).toMatchObject({
           setup_for_company: true,
-          selected_group: undefined,
+          selected_group: '30',
           new_user: false,
           redirect_after_success: '/path/to/redirect/',
           customer: {

ee/spec/frontend/subscriptions/buy_minutes/mock_data.js

@@ -38,7 +38,7 @@ export const stateData = {
     __typename: 'Subscription',
   },
   redirectAfterSuccess: '/path/to/redirect/',
-  selectedNamespaceId: null,
+  selectedNamespaceId: '30',
   selectedPlanId: null,
   paymentMethod: {
     id: null,