Avoid referencing the current device in `LaunchConfig`

[leofang]

This is strictly speaking not 100% safe:

cuda-python/cuda_core/cuda/core/experimental/_launch_config.py

Lines 68 to 86 in bf590e4

	# FIXME: Calling Device() strictly speaking is not quite right; we should instead
	# look up the device from stream. We probably need to defer the checks related to
	# device compute capability or attributes.
	# thread block clusters are supported starting H100
	if self.cluster is not None:
	if not _use_ex:
	err, drvers = driver.cuDriverGetVersion()
	drvers_fmt = f" (got driver version {drvers})" if err == driver.CUresult.CUDA_SUCCESS else ""
	raise CUDAError(f"thread block clusters require cuda.bindings & driver 11.8+{drvers_fmt}")
	cc = Device().compute_capability
	if cc < (9, 0):
	raise CUDAError(
	f"thread block clusters are not supported on devices with compute capability < 9.0 (got {cc})"
	)
	self.cluster = cast_to_3_tuple("LaunchConfig.cluster", self.cluster)
	if self.shmem_size is None:
	self.shmem_size = 0
	if self.cooperative_launch and not Device().properties.cooperative_launch:
	raise CUDAError("cooperative kernels are not supported on this device")

because we could be changing the device after creating a launch config and before we use it to launch a kernel (on another device).