Emergency Contact Phone Number doesn't account for int'l contacts

[RigelAC]

If someone attending the convention from abroad wants their parents in, say, London to be their emergency contact, the Emergency Contact Phone Number field does not allow for non-US numbers. Should do the same as the Postal Code field and have an "outside US" checkbox that removes restrictions on the field.

[EliAndrewC]

So the logic for why we required it this way was that we specifically wanted there to be someone in the US whom we could call if an attendee got sent to the hospital. I guess since international calls are indeed a thing, it's probably okay to just have an international number.

[kitsuta]

We no longer validate ec_phone this way, so it's fixed.