community/pipewire: fix issue with autostarting on gnome-session

Some desktop environments that use gnome-session cannot start pipewire in the 'Initialization' phase, and the phase times out waiting for pipewire. There doesn't seem to be any phase that pipewire can start up in successfully with gnome-session, except the very last one.

Also see: https://gitlab.com/postmarketOS/pmaports/-/issues/963

Reported upstream: https://gitlab.freedesktop.org/pipewire/pipewire/-/issues/926