[plasma-mobile-dev] Switch to pipewire

In my recent tests on Plasma Mobile, Pipewire has been pretty good and
almost no issues.

The only issue I have encounterered so far has been this one:
https://gitlab.com/mobian1/callaudiod/-/issues/25


which seems to be a callaudiod specific issue, so would also be
happening with pulseaudio anyway.

Signed-off-by: Dan Johansen <strit@manjaro.org>