fix attribute check for SQLAlchemy labeled column properties (#5567)

Author: benedikt-bartscher

reflex/utils/types.py

@@ -478,7 +478,7 @@ def get_attribute_access_type(cls: GenericType, name: str) -> GenericType | None
                         if type_ in PrimitiveToAnnotation:
                             type_ = PrimitiveToAnnotation[type_]
                         type_ = type_[item_type]  # pyright: ignore [reportIndexIssue]
-                if column.nullable:
+                if hasattr(column, "nullable") and column.nullable:
                     type_ = type_ | None
                 return type_
         if name in insp.all_orm_descriptors: