Summary:
`git config --global --add safe.directory` is no longer necessary because is done inside the Docker container.

## Changelog:

[INTERNAL] - Remove unnecessary git config --global --add safe.directory

Pull Request resolved: https://github.com/facebook/react-native/pull/45663

Test Plan: CI

Reviewed By: blakef

Differential Revision: D60229662

Pulled By: cortinico

fbshipit-source-id: aa817ff27adaab3e3105ab22af74a871b377295b