KDE: Update KDE Plasma to 6.6.0

Announcement: https://kde.org/announcements/plasma/6/6.6.0/

The Digital Clock applet now uses timerfd(2) which may cause
high CPU usage on FreeBSD due to bug [1]. As a workaround
tweak Clock settings to not show seconds.

Ports changes:

graphics/plasma6-spectacle:

• Require KQuickImageEditor

security/plasma6-ksshaskpass:

• Switch from KWallet to QtKeychain

sysutils/plasma6-kinfocenter:

• Add dependence on aha
• pactl comes from pulseaudio, not pipewire
• Replace ip with ifconfig [2]

sysutils/plasma6-ksystemstats:

• Backport upstream patch to enable network info on FreeBSD

x11-themes/plasma6-aurorae:

• Fix patch
• Renew USE_KDE

x11-toolkits/plasma6-kdeplasma-addons:

• Drop stale dependencies

x11-wm/plasma6-kwin:

• Drop stale dependencies

x11/plasma6-libkscreen:

• Clean up Makefile

x11/plasma6-plasma-workspace:

• Drop stale dependencies
• Drop stale cmake args

PR: 293368 [1]
PR: 285230 [2]