Make approvalRequired and subscriptionsLimit nullable

When the value of subscriptionRequired is set to false to other values must not be included in the extracted template

Author: Frederic-roamler

src/APIM_ARMTemplate/apimtemplate/Common/TemplateModels/ProductsTemplateResource.cs

@@ -11,8 +11,8 @@ public class ProductsTemplateProperties
         public string description { get; set; }
         public string terms { get; set; }
         public bool subscriptionRequired { get; set; }
-        public bool approvalRequired { get; set; }
-        public int subscriptionsLimit { get; set; }
+        public bool? approvalRequired { get; set; }
+        public int? subscriptionsLimit { get; set; }
         public string state { get; set; }
         public string displayName { get; set; }
     }