`test_graph.py` fails with `cuda-python==12.6.*`

[leofang]

We probably missed a few version checks in the graph implementation.

FAILED test_graph.py::test_graph_straight - AttributeError: type object 'CUgraphInstantiateResult' has no attribute 'CUDA_GRAPH_INSTANTIATE_CONDITIONAL_HANDLE_UNUSED'
FAILED test_graph.py::test_graph_fork_join - AttributeError: type object 'CUgraphInstantiateResult' has no attribute 'CUDA_GRAPH_INSTANTIATE_CONDITIONAL_HANDLE_UNUSED'
FAILED test_graph.py::test_graph_is_join_required - AttributeError: type object 'CUgraphInstantiateResult' has no attribute 'CUDA_GRAPH_INSTANTIATE_CONDITIONAL_HANDLE_UNUSED'
FAILED test_graph.py::test_graph_repeat_capture - AttributeError: type object 'CUgraphInstantiateResult' has no attribute 'CUDA_GRAPH_INSTANTIATE_CONDITIONAL_HANDLE_UNUSED'
FAILED test_graph.py::test_graph_capture_errors - AttributeError: type object 'CUgraphInstantiateResult' has no attribute 'CUDA_GRAPH_INSTANTIATE_CONDITIONAL_HANDLE_UNUSED'
FAILED test_graph.py::test_graph_conditional_if[True] - AttributeError: type object 'CUgraphInstantiateResult' has no attribute 'CUDA_GRAPH_INSTANTIATE_CONDITIONAL_HANDLE_UNUSED'
FAILED test_graph.py::test_graph_conditional_if[False] - AttributeError: type object 'CUgraphInstantiateResult' has no attribute 'CUDA_GRAPH_INSTANTIATE_CONDITIONAL_HANDLE_UNUSED'
FAILED test_graph.py::test_graph_conditional_if_else[True] - AssertionError: Regex pattern did not match.
FAILED test_graph.py::test_graph_conditional_if_else[False] - AssertionError: Regex pattern did not match.
FAILED test_graph.py::test_graph_conditional_switch[0] - AssertionError: Regex pattern did not match.
FAILED test_graph.py::test_graph_conditional_switch[1] - AssertionError: Regex pattern did not match.
FAILED test_graph.py::test_graph_conditional_switch[2] - AssertionError: Regex pattern did not match.
FAILED test_graph.py::test_graph_conditional_switch[3] - AssertionError: Regex pattern did not match.
FAILED test_graph.py::test_graph_conditional_while[True] - AttributeError: type object 'CUgraphInstantiateResult' has no attribute 'CUDA_GRAPH_INSTANTIATE_CONDITIONAL_HANDLE_UNUSED'
FAILED test_graph.py::test_graph_conditional_while[False] - AttributeError: type object 'CUgraphInstantiateResult' has no attribute 'CUDA_GRAPH_INSTANTIATE_CONDITIONAL_HANDLE_UNUSED'
FAILED test_graph.py::test_graph_child_graph - AttributeError: type object 'CUgraphInstantiateResult' has no attribute 'CUDA_GRAPH_INSTANTIATE_CONDITIONAL_HANDLE_UNUSED'
FAILED test_graph.py::test_graph_update - AssertionError: Regex pattern did not match.
FAILED test_graph.py::test_graph_stream_lifetime - AttributeError: type object 'CUgraphInstantiateResult' has no attribute 'CUDA_GRAPH_INSTANTIATE_CONDITIONAL_HANDLE_UNUSED'
FAILED test_graph.py::test_graph_complete_options - AttributeError: type object 'CUgraphInstantiateResult' has no attribute 'CUDA_GRAPH_INSTANTIATE_CONDITIONAL_HANDLE_UNUSED'