Fix Tensor __radd__ type hint issue (#35231)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/35231
Fixes #35213
(Note: this ignores all push blocking failures!)
Test Plan: `mypy -c "import torch; ten = torch.tensor([1.0, 2.0, 3.0]); print(7 + ten)"` should not produce any warnings
Differential Revision: D20604924
Pulled By: pbelevich
fbshipit-source-id: 53a293a99b3f2ab6ca5516b31f3a92f67eb67a39
