[RUBY-2477] Cache copy cards order in memory before transient registr…

…ation is deleted

app/services/waste_carriers_engine/order_copy_cards_completion_service.rb

@@ -15,6 +15,9 @@ def run(transient_registration)
     private
 
     def complete_order_copy_cards
+      # Called to get copy cards order before transient registration is deleted later
+      cached_copy_cards_order
+
       update_registration
 
       delete_transient_registration
@@ -44,16 +47,16 @@ def delete_transient_registration
     def send_confirmation_email
       if @transient_registration.unpaid_balance?
         Notify::CopyCardsAwaitingPaymentEmailService
-          .run(registration: registration, order: copy_cards_order)
+          .run(registration: registration, order: cached_copy_cards_order)
       else
         Notify::CopyCardsOrderCompletedEmailService
-          .run(registration: registration, order: copy_cards_order)
+          .run(registration: registration, order: cached_copy_cards_order)
       end
     rescue StandardError => e
       Airbrake.notify(e, registration_no: registration.reg_identifier) if defined?(Airbrake)
     end
 
-    def copy_cards_order
+    def cached_copy_cards_order
       @_copy_cards_order ||= transient_registration.reload.finance_details.orders.last
     end
   end