nixos/systemd: fix service `sshd-vsock@` (#508855)

        pamMount = false;

      };

    };

    # the systemd vmspawn credential dropin executes sshd and expects ExecSearchPath to be set, see:

    # https://github.com/systemd/systemd/blob/v259.3/src/vmspawn/vmspawn.c#L2662

    # this service is used, for example, when NixOS is started via systemd-vmspawn

    systemd.services."sshd-vsock@" = mkIf config.services.openssh.enable {

      serviceConfig.ExecSearchPath = "${config.services.openssh.package}/bin";

      overrideStrategy = "asDropin";

    };

  };

  # FIXME: Remove these eventually.