Reinitializing the pipewire library after calling pw_deinit() causes crashes in subsequent pipewire api calls

Minimal example to reproduce the crash: pw_deinit_crash.c

I noticed this while playing around with a (not upstream) mpv pipewire backend. mpv destroys it's audio backends when you e.g. unselect the audio track - where it seems to make sense to call pw_deinit() - and initializes them again when you reselect an audio track, which then crashes in pipewire.

For reference, the pipewire backend PR that i used as a base: https://github.com/mpv-player/mpv/pull/7902/commits/918b2873db331b43b1716526d454881411e66324