More lingering dependencies on kf5 in testing

Looks like newer konqueror is stuck in unstable, due to qt6-webengine-dev
having
only limited architecture support. I suppose konqueror itself needs to be
aligned
with qt6-webengine-dev architectures list to get it unstuck, which will
remove
the need for a bunch of lingering kf5 packages in testing

https://tracker.debian.org/pkg/konqueror

Another one that still remains is kup-backup, but that would need to be
updated to newer version and rebuilt against Kf 6 / Qt 6.

Regards,
Shmerl.