x11/plasma5-plasma-workspace: QA improvements

Add missing pkg-plist entries after my rushed and pointy-hat-worthy
commit 353079b68987. [1] I was under the impression that this version
just contained the security fixes and didn't do my due diligence.

To sort of make up for it:

Add other missing pkg-plist entries if kuserfeedback is installed and
add it as a dependency.

Potentially improve wayland support by adding plasma-wayland-protocols
and wayland-protocols as build dependencies.

Add PIPEWIRE option and patch out auto-detection. Enable by default as
x11/plasma5-plasma-desktop also enables PIPEWIRE by default.

Remove ancient CONFLICTS.

PR: 279744 [1]
Reported by: jbeich [1]
MFH: 2024Q2

(cherry picked from commit c75e3897416092ecd7dd255114dae100734524d7)