test_process_device throws an error on when cuda is available

[janfb]

Describe the bug
The test for device handling seems to require the wrong output. It should not fail on a cuda capable machine.

To Reproduce
pytest tests/torchutils_test.py::test_process_device

Expected behavior
the test should pass.

Additional context

...............xxxx......x............................................................................................. [100%]
============================================================ FAILURES ============================================================
___________________________________________________ test_process_device[cuda] ____________________________________________________

device_input = 'cuda'

@pytest.mark.parametrize("device_input", ("cpu", "gpu", "cuda", "cuda:0", "mps"))
def test_process_device(device_input: str) -> None:
    """Test whether the device is processed correctly."""

    try:
        device_output = torchutils.process_device(device_input)
        if device_input == "cpu":
            assert device_output == "cpu"
        elif device_input == "gpu":
            if torch.cuda.is_available():
                current_gpu_index = torch.cuda.current_device()
                assert device_output == f"cuda:{current_gpu_index}"
            elif torch.backends.mps.is_available():
                assert device_output == "mps:0"

        if device_input == "cuda" and torch.cuda.is_available():

          assert device_output == "cuda:0"

E AssertionError: assert 'cuda' == 'cuda:0'
E
E - cuda:0
E ? --
E + cuda

../sbi/tests/torchutils_test.py:219: AssertionError