Check international number for alpha: NO if true then use number to send

SMS.

This is not a catch all for international SMS, the rules are quite
complex and still not completely understood. We are talking with our
provider who maybe able to sort this out for us. But in the meantime,
this should solve for the case that we understand.

tests/app/user/test_rest.py

@@ -315,7 +315,7 @@ def test_post_user_attribute_with_updated_by_sends_notification_to_international
 ):
     updater = create_user(name="Service Manago")
     update_dict = {
-        'mobile_number': '601117224412',
+        'mobile_number': '+601117224412',
         'updated_by': str(updater.id)
     }
     auth_header = create_authorization_header()