Fix import formatting in test_registry_cleanup

Made-with: Cursor

Author: Andy-Jost

cuda_core/tests/graph/test_graphdef.py

@@ -727,6 +727,7 @@ def test_identity_preservation(init_cuda):
 def test_registry_cleanup(init_cuda):
     """Node registry entries are removed on destroy() and graph teardown."""
     import gc
+
     from cuda.core._graph._graph_def._graph_node import _node_registry
 
     def registered(node):