mail/fetchmail: update to 6.5.7

Adds Italian translation, which was revived by Luca Vercelli (thanks!)

Changelog: https://gitlab.com/fetchmail/fetchmail/-/releases#fetchmail-657-released-2025-10-18-32215-loc
PR: 290347
MFH: 2025Q4
Approved by: Corey Halpin (maintainer)