Should accept `undefined` as well as `null` as missing optional argument

[leonerd]

For ages I was struggling with the following code

return client.messages.sendMessage(peer, message, Math.random() * (1<<30));

returning INPUT_FETCH_ERROR from Telegram. Much code-diving later reveals that I have to call

return client.messages.sendMessage(peer, message, Math.random() * (1<<30), null, null, null);

i.e. that only null works as missing arguments, not undefined.

[leonerd]

The line of code responsible appears to be https://github.com/goodmind/telegram-tl-node/blob/master/lib/builder/constructor-builder.js#L185