Remove obsolete type guard on toLua function.

pkgs/luaUtils.nix

@@ -127,9 +127,6 @@ let
         # can be: null, bool, string, path, int, float, list, set or lambda
         type = builtins.typeOf value;
       in
-      assert
-        !(builtins.isFunction type)
-        || builtins.throw "Nix functions (${type}) have no correspoinding Lua representation.";
       {
         "null" = nullToLua;
         "bool" = boolToLua;