Fix property link bug in LookupFactory

InABox.Core/ILookupDefinition.cs

@@ -130,7 +130,7 @@ namespace InABox.Core
                     return property.Parent;
                 }
             }
-            return DatabaseSchema.Property(T, $"{column}.{nameof(IEntityLink.ID)}");
+            return DatabaseSchema.Property(T, $"{column}.{nameof(IEntityLink.ID)}")?.Parent;
         }
 
         private static ILookupDefinitionGenerator? GetLookupGenerator(IProperty? property)