bug#45280: qutebrowser has no audio

[bdju]

Here's some output when I launch qutebrowser from a terminal. It seems
like it may be using ALSA instead of pulse for some reason.
```
ALSA lib pcm_dmix.c:1075:(snd_pcm_dmix_open) unable to open slave
[14812:14812:0421/184051.727290:ERROR:alsa_util.cc(204)] PcmOpen:
default,No such file or directory
ALSA lib pcm_dmix.c:1075:(snd_pcm_dmix_open) unable to open slave
[14812:14812:0421/184051.728902:ERROR:alsa_util.cc(204)] PcmOpen:
plug:default,No such file or directory
[14656:13:0421/184058.289956:ERROR:batching_media_log.cc(38)]
MediaEvent: {"error":"FFmpegDemuxer: no supported streams"}
[14656:1:0421/184058.290464:ERROR:batching_media_log.cc(35)] MediaEvent:
{"pipeline_error":14}
libpng warning: iCCP: known incorrect sRGB profile
libpng warning: iCCP: known incorrect sRGB profile
ALSA lib pcm_dmix.c:1075:(snd_pcm_dmix_open) unable to open slave
[14812:14812:0421/184144.908489:ERROR:alsa_util.cc(204)] PcmOpen:
default,No such file or directory
ALSA lib pcm_dmix.c:1075:(snd_pcm_dmix_open) unable to open slave
[14812:14812:0421/184144.911093:ERROR:alsa_util.cc(204)] PcmOpen:
plug:default,No such file or directory
```