Ex8 instructions updated for custom exception code change

Author: ChrisHowd

Instructions/Labs/LAB_AK_08_refactor_large_functions.md

@@ -93,6 +93,7 @@ Use the following steps to download the sample project and open it in Visual Stu
             - src\
                 - ECommerce.ApplicationCore\
                     - Entities\
+                    - Exceptions\
                     - Interfaces\
                     - Services\
                         - OrderProcessor.cs