RTCDataChannel label cannot be empty string

[gitlaura]

I'm working on an app that sometimes sets a new RTCDataChannel's label to "". I believe this is technically okay, however iosrtc throws an error here.

if (!label || typeof label !== 'string') {
  throw new Error('label argument required');
}

Can you update it so that an empty string passes? i.e.,
if ((!label && label !== "") || typeof label !== 'string')

[ibc]

Done.