[desktop-kit] `app-office/libreoffice-bin kde` blocks `kde6` with explicit dep on a few `kde-frameworks/.*:5`

Here's the relevant line from the `emerge` output:
```
kde-frameworks/kio:5 required by (app-office/libreoffice-bin-25.8.5.2:0/0::desktop-kit, ebuild scheduled for merge) USE="gtk kde -amd64 (-arm64) -gnome -java"
```
In `RDEPEND` in the ebuild:
```
kde? (
dev-qt/qtcore:5
dev-qt/qtgui:5
dev-qt/qtwidgets:5
dev-qt/qtx11extras:5
kde-frameworks/kconfig:5
kde-frameworks/kcoreaddons:5
kde-frameworks/ki18n:5
kde-frameworks/kio:5
kde-frameworks/kwindowsystem:5
)
```
I observed `kde-frameworks/kio:5` as the problematic package, but it turned out to be more.

Start with the app-office/libreoffice-bin ebuild and inspect the RDEPEND block shown in the issue, especially the KDE-related entries. Reproduce the emerge dependency resolution with kde6 enabled, then update the dependency declarations so the reported KDE 5 constraints no longer block it and verify the package can be scheduled successfully.

Written by the indexing model from the issue text.