Section 7. Failure by any issuing authority to take final action on a permit or approval within the 180–day period or extended time, if applicable, shall be considered a grant of the relief requested of that authority. In that event, within 14 days after the date of expiration of the time period, the applicant shall file an affidavit with the city or town clerk, attaching the application, setting forth the facts giving rise to the grant and stating that notice of the grant has been mailed, by certified mail, to all parties to the proceedings and all persons entitled to notice of hearing in connection with the application.