Remove known issue section for PipeWire

[EbonJaeger]

Description

Removes the Known Issues section for PipeWire. It will no longer be needed since the only issue there has been fixed in Unstable at the time of writing.

Submitter Checklist

• [ ] Squashed commits with git rebase -i (if needed)

[davidjharder]

Most of that page can be removed can't it?

[carlberger]

The verification of the sound server as shown in the page works only if LANG is set to english, so the code could be

LANG=en pactl info | grep '^Server Name'

[TraceyC77]

LGTM