Fix co-dev regresssion in github-exports-check job (#95345)
Summary:
Regression introduced in #91134 (github-exports-check calls git, which is not available internally at Meta).
Meta employees, see T145865943 for the context.
Test Plan: Unit tests, `github-export-checks` job.
Differential Revision: D43521051
Pull Request resolved: https://github.com/pytorch/pytorch/pull/95345
Approved by: https://github.com/kit1980
