mail/imapsync: Upgrade port to 2.314
Approved by: jrm (mentor), otis (mentor), pi (maintainer timeout)
MFH: 2025Q4
Differential Revision: https://reviews.freebsd.org/D52752
Changelog: https://imapsync.lamiral.info/ChangeLog
(cherry picked from commit 2c546142a90ef690d0f7624dfd1c907889c9f18b)