has_phone passes for invalid phone numbers

[HawkiesZA]

We've been testing out has_phone in some of our flows and noticed that it's quite liberal in what passes for a phone number. In the code it seems that it's just parsing and formatting the given number and not actually calling is_possible_number and is_valid_number on it. This means that people can basically input anything with 2 or more digits and it will "validate" as a phone number.

[smn]

I think #225 fixes it. It'll be part of the next release.