This reverts commit 04228de666.
Anki 25.01 Beta 1 revealed a bunch of regressions with the latest
Qt, and zero reports of improvements from it, so we'll be better off
holding off on it for now, and perhaps reporting the deadkeys issue
to Qt once we've got a proper reproduction process.
* Qt 6.8.1
Bumps minimum glibc to 2.35, and minimum macOS to 12
* Drop generation of Qt5 packaged build
Closes#3615
* Include qt6 requirements in aqt wheel; drop extra deps
* Fix aqt wheels growing over time
