When using e.g. `{ addr = "[::]"; port = 22; }` at `listenAddresses`,
the check fails because of an escaping issue[1] with
last 1 log lines:
> Invalid test mode specification -f
For full logs, run 'nix log /nix/store/c6pbpw5hjkjgipmarwyic9zyqr1xaix5-check-sshd-config.drv'
Using `lib.escapeShellArg` appears to solve the problem.
[1] https://github.com/NixOS/nixpkgs/pull/256090#issuecomment-1738063528