Error: unsupported locales detected

[kuwii]

Describe the bug

When using systemd-boot, installing NixOS or updating system using nixos-rebuild will fail at glibc-locales with error

Error: unsupported locales detected:
en_US.utf8/UTF8

Steps To Reproduce

Steps to reproduce the behavior:

1. Download this unstable version NixOS image.
2. Use installer to install NixOS.

• Location: Asia/Shanghai
• Partitions: Erase entire disk and enable swap

3. The installation process will fail with message described in the description.

Expected behavior

Can install NixOS or update system.

Screenshots

Additional context

No

Notify maintainers

Ping maintainers of glibc-locales.

@edolstra @Ma27

Metadata

Please run nix-shell -p nix-info --run "nix-info -m" and paste the result.

 - system: `"x86_64-linux"`
 - host os: `Linux 5.15.52, NixOS, 22.11 (Raccoon), 22.11pre389925.a5c867d9fe9`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.9.1`
 - channels(root): `"nixos-22.11pre389925.a5c867d9fe9"`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixos`

[vlinkz]

I made a fix for the installer to use the default locale format, that way any issues surrounding #179486 shouldn't be broken by more changes down the line. I'll make a PR soon once I finish some more testing