PySide6: Update to 6.8.1.1

This should have been part of the Qt 6.8.1 update, but upstream never
published distfiles for 6.8.1 for some reason, so we shipped the lastest
compatible version 6.8.0.2 instead. Version 6.8.1.1 is a small bugfix
release on top of what would have been 6.8.1 release.

MFH: 2025Q1