fix: topup checkout flaky test (#13616)

spec/enterprise/services/enterprise/billing/topup_checkout_service_spec.rb

@@ -44,17 +44,19 @@ describe Enterprise::Billing::TopupCheckoutService do
     end
 
     it 'raises error for invalid credits' do
-      expect do
-        service.create_checkout_session(credits: 500)
-      end.to raise_error(Enterprise::Billing::TopupCheckoutService::Error)
+      expect { service.create_checkout_session(credits: 500) }.to raise_error do |error|
+        expect(error.class.name).to eq('Enterprise::Billing::TopupCheckoutService::Error')
+        expect(error.message).to eq(I18n.t('errors.topup.invalid_option'))
+      end
     end
 
     it 'raises error when account is on free plan' do
       account.update!(custom_attributes: { plan_name: 'Hacker', stripe_customer_id: stripe_customer_id })
 
-      expect do
-        service.create_checkout_session(credits: 1000)
-      end.to raise_error(Enterprise::Billing::TopupCheckoutService::Error)
+      expect { service.create_checkout_session(credits: 1000) }.to raise_error do |error|
+        expect(error.class.name).to eq('Enterprise::Billing::TopupCheckoutService::Error')
+        expect(error.message).to eq(I18n.t('errors.topup.plan_not_eligible'))
+      end
     end
   end
 end