KDE: Update KDE Plasma Desktop to 5.23.4

Tuesday, 30 November 2021. Today KDE releases a bugfix update to KDE
Plasma 5, versioned 5.23.4.

Plasma 5.23 was released in October 2021 with many feature refinements
and new modules to complete the desktop experience.

This release adds three weeks' worth of new translations and fixes from
KDE's contributors. The bugfixes are typically small but important and
include:

• Breeze style: Reduce groove opacity for greater contrast with scrollbar/slider/etc.
• Applets/weather: Make cursor a pointing hand when hovering over source link.
• Plasma Systemmonitor: Don’t make right click popup modal.

Announcement:
https://kde.org/announcements/plasma/5/5.23.4/

Changelog:
https://kde.org/announcements/changelogs/plasma/5/5.23.3-5.23.4/