Map BackOfficeNotification in ContentMapDefinitions (#13874)

* Map Notifications

* Empty line

(cherry picked from commit 5158d8119d)

src/Umbraco.Web.BackOffice/Mapping/ContentMapDefinition.cs

@@ -162,6 +162,11 @@ internal class ContentMapDefinition : IMapDefinition
         target.Updater = source.Updater;
         target.Urls = source.Urls;
         target.Variants = context.MapEnumerable<ContentVariantDisplay, ContentVariantScheduleDisplay>(source.Variants);
+
+        foreach (BackOfficeNotification backOfficeNotification in source.Notifications)
+        {
+            target.Notifications.Add(backOfficeNotification);
+        }
     }
 
     // Umbraco.Code.MapAll