Disallow running CLI with root privileges (#32583)

In #31331, I made a change that prevents Zed from running with root
privileges, but I forgot about the CLI.
So if you run the CLI without the `--foreground` flag, it just freezes
without any messages. This PR fixes that.

Release Notes:

- N/A
628f91dd96Yaroslav Pietukhov committed on 6/13/2025, 5:09:32 PM· committed by GitHubparent3fb28f6
6 files changedLine totals unavailable