add pytorch directory into Exclusions of Windows Defender
There's still [mt.exe exception in nightly CI](https://github.com/pytorch/pytorch/runs/5783636743?check_suite_focus=true#step:11:7204)
It looks that issue #66278 hasn't been resolved.
It might have something with windows defender.
So, we could try adding the pytorch directory into Windows defender exclusions and see the data in the next weeks.
verification link:
https://github.com/pytorch/pytorch/runs/5854202308?check_suite_focus=true#step:3:55
Pull Request resolved: https://github.com/pytorch/pytorch/pull/75313
Approved by: https://github.com/malfet
