KDE: Update KDE Gear to 25.04.0

Announcement: https://kde.org/announcements/gear/25.04.0/

Ports changes:

kde.mk:

• Simplify KDE_APPS_BASED_PATCHLEVEL definition and generalize it for unstable branch.

devel/kopeninghours:

• Use custom PLIST_SUB to reduce churn on updates.

editors/ghostwriter:

• Drop upstreamed patch.

games/khangman:

• Drop upstreamed patch.

math/kcalc:

• Depend on math/mpc.

multimedia/kdenlive:

• Prevent fetching during build.
• Depends on KF6 Purpose unconditionally and remove no-op OPTIONS_SUB.
• Depend on OpenTimelineIO.

net/krdc:

• Switch to freerdp3.

x11-fm/dolphin:

• Fix abuse of PLIST_SUB.

*/*:

• Add missing and update KF6 dependencies and Qt components.