[bug] Cancelling out of new Node QR scanner throws Error exception alert in UI
When I go to add a node using the new QR scan feature and then press the cancel button in the camera scanner that pops up in iOS, Cake wallet throws up an 'Error: Exception: Unexpected scan QR code value: value is empty.'  

I think the native camera cancelling just needs to be handled more gracefully (i.e. no alerts at all, just take me back to the app where I was before).  