Check metaclass error_code property properly

Signed-off-by: Andres Gomez Ferrer <andresg@spotify.com>

Author: andresgomezfrr

flytekit/exceptions/user.py

@@ -31,7 +31,7 @@ def value(self):
 
     @property
     def error_code(self):
-        return self.value.error_code if hasattr(self.value, "error_code") else self._ERROR_CODE
+        return self.value.__class__.error_code if hasattr(self.value.__class__, "error_code") else self._ERROR_CODE
 
 
 class FlyteTypeException(FlyteUserException, TypeError):