[GraphBolt][CUDA] `cpu-cuda` optimization

## 🔨Work Item

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Project tracker: https://github.com/orgs/dmlc/projects/2

## Description

We should consider moving the `copy_to` operation before the feature fetch stage so that the overlap optimization is enabled for the `cpu-cuda` mode as well. However, the features need to be pinned for this to work. On my machine, I got a 2.2x speedup by doing so.

```python
if args.storage_device == "cpu":
datapipe = datapipe.copy_to(device=device, extra_attrs=["input_nodes"])
```

@Rhett-Ying @frozenbugs