Extract out fact check email validation
Extract out fact check email validation

Further gains made by extracting the email validation logic out. It only needs
to change the message so this really slims down #progress.

alphagov/publisher,telekomatrix/publisher,theodi/publisher,theodi/publisher,alphagov/publisher,leftees/publisher,theodi/publisher,leftees/publisher,telekomatrix/publisher,leftees/publisher,theodi/publisher,telekomatrix/publisher,telekomatrix/publisher,alphagov/publisher,leftees/publisher