Provide built-in way to use bundled torch shape fixtures without copy-paste

### Describe the Bug

in https://pyrefly.org/en/docs/tensor-shapes-setup/#configuration

link point to https://github.com/facebook/pyrefly/tree/main/pyrefly/test/tensor_shapes/fixtures

but it should be

https://github.com/facebook/pyrefly/tree/main/test/tensor_shapes/fixtures

and manually copy paste it is too complex.

I suggest provide a config to just read the torch pyi bundled with pyrefly. (or a separate pyi stub package?)

### Sandbox Link

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### (Only applicable for extension issues) IDE Information

_No response_