Fix showing contact numbers of unknown type
Returning NULL for unknown types will result in the concatinated string to be NULL, which hides the phone number added to the label.
Fix it by always returning a valid string.
/cc @guido.gunther
Due to an influx of spam, we have had to impose restrictions on new accounts. Please see this wiki page for instructions on how to get full permissions. Sorry for the inconvenience.
Returning NULL for unknown types will result in the concatinated string to be NULL, which hides the phone number added to the label.
Fix it by always returning a valid string.
/cc @guido.gunther