message: Return a detached object if a PK doesn't exist rather than throwing
diff: @@ -306,7 +306,7 @@ Object Object::get_for_primary_key(ContextType& ctx, std::shared_ptr<Realm> cons
  if (!table)
  return Object(realm, object_schema, Obj());
  auto key = get_for_primary_key_impl(ctx, *table, *primary_prop, primary_value);
  - return Object(realm, object_schema, table->get_object(key));
  + return Object(realm, object_schema, key ? table->get_object(key) : Obj{});
  }
  template<typename ValueType, typename ContextType>
  