Revert "Merge branch 'pks-gitaly-stop-writing-gitconfig' into 'master'"

What does this MR do?

This reverts !6128 (merged) because it's likely this change caused a production incident: gitlab-com/gl-infra/production#7284 (closed). We saw over 50 git for-each-ref processes iterating through the gitlab-org/gitlab pool repository, which suggests the alternateRefsCommand isn't specified somewhere where it should (possibly RepositorySize).

Related issues

gitlab-com/gl-infra/production#7284 (closed)

Checklist

See Definition of done.

For anything in this list which will not be completed, please provide a reason in the MR discussion

Required

• Merge Request Title, and Description are up to date, accurate, and descriptive
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Expected (please provide an explanation if not completing)

• Test plan indicating conditions for success has been posted and passes
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