launch: avoid autostarting pipewire-pulse systemd units for root

Long story short, this is something pulseaudio has since 2017 [1]. If
pipewire-pulse is aiming to be a drop-in replacement, the same behaviour
is probably expected.

I noticed that without this line I hit some issues with systemd socket
activation. In fact, it does not work properly at all. It probably has
something to do with the fact that pipewire-pulse is started for GDM
session and is somehow propagated down to my own user session.

[1] 24928d6b6f

src/daemon/systemd/user/pipewire-pulse.service.in

@@ -14,6 +14,7 @@ Description=PipeWire PulseAudio
 # After=pipewire-pulse.socket is not needed, as it is already implicit in the
 # socket-service relationship, see systemd.socket(5).
 Requires=pipewire-pulse.socket
+ConditionUser=!root
 
 [Service]
 Type=simple

src/daemon/systemd/user/pipewire-pulse.socket

@@ -1,5 +1,6 @@
 [Unit]
 Description=PipeWire PulseAudio
+ConditionUser=!root
 
 [Socket]
 Priority=6