ci: fix git clone depth being too small, and typo in debug msg

Technically this option can be configured in the Gitlab UI, but I spent about 3 hours debugging a CI failure caused by it being too low and I don't want to risk forgetting this can happen later if/when someone decides to lower it in the UI. By setting it here, we can have some context/history about why.

This fixes the CI in !5688 (merged)

Also see: https://docs.gitlab.com/17.4/ee/user/project/repository/monorepos/index.html#shallow-cloning