_get_node_attribute_at_index() raising AttributeError instead of Valu…

…eError (#20156)

#20155

This commit allows using hasattr() on on node attributes, without raising an error.

keras/src/ops/operation.py

@@ -282,7 +282,7 @@ def _get_node_attribute_at_index(self, node_index, attr, attr_name):
             The operation's attribute `attr` at the node of index `node_index`.
         """
         if not self._inbound_nodes:
-            raise ValueError(
+            raise AttributeError(
                 f"The layer {self.name} has never been called "
                 f"and thus has no defined {attr_name}."
             )