pulseaudio: Actually keep the connection around

PulseAudio is event-based so it does not do much harm

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>
j4status: Only trigger display if a section changed

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>