clean up mypy nit in torch/jit/_recursive.py (#66253)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/66253
This was initially broken in #65829 and unbroken in #66003, this PR cleans
it up by removing the mypy ignore line.
Test Plan:
```
mypy torch/jit/_recursive.py --no-incremental
```
Imported from OSS
Reviewed By: supriyar
Differential Revision: D31475100
fbshipit-source-id: 46ab2ede72c08b926f4f9a6b03b1a1375b884c8a
