ensure properties reset on deep clone of ContentType (this is just a fail safe check)

src/Umbraco.Core/Models/ContentType.cs

@@ -151,6 +151,9 @@ namespace Umbraco.Core.Models
             clone.PropertyTypes = PropertyTypeCollection
                 .Where(x => x.PropertyGroupId == null)
                 .Select(x => (PropertyType)x.DeepClone()).ToList();
+
+            clone.ResetDirtyProperties(false);
+
             return clone;
         }