nixos/octoprint: fix ipv6 host (#351721)

  baseConfig = {

    plugins.curalegacy.cura_engine = "${pkgs.curaengine_stable}/bin/CuraEngine";

    server.host = cfg.host;

    server.port = cfg.port;

    webcam.ffmpeg = "${pkgs.ffmpeg.bin}/bin/ffmpeg";

  };

  } // lib.optionalAttrs (cfg.host != null) {server.host = cfg.host;};

  fullConfig = lib.recursiveUpdate cfg.extraConfig baseConfig;

      enable = lib.mkEnableOption "OctoPrint, web interface for 3D printers";

      host = lib.mkOption {

        type = lib.types.str;

        default = "0.0.0.0";

        type = lib.types.nullOr lib.types.str;

        default = null;

        description = ''

          Host to bind OctoPrint to.

        '';