Cleanup jackd backwards compatibility on Linux

[porras]

(Followup to #3347 and #3349 and the discussions there)

Sonic Pi depends already on pipewire on Linux (since https://github.com/sonic-pi-net/sonic-pi/pull/3349/files#diff-2ca3189a9188d736a9e846057be42fa4b7727274ac6e0152bc0320031f73ad7dR1178) so all this was already dead code.

[rbnpi]

Oops. I think I've boobed on my statement about linux going entirely pipewire. I had sgtriped out the linux alternative on my daemon.rb I'd be happy for it to happen, but I don't know how may would b e trying to build 4.5 on linux versions which don't have pipewire support and who still want to use jackd and pulseaudio. Ubuntu and Debian latest are fine for pipewire. I don;t know enough out other current distros. Maybe leave this for a bit?
BTW tried your flatpak on Ubuntu 23 running as a virtual machine on my M2 Mac. No problems installing, although flatpak is rather slow to download packages.

[porras]

Makes sense. Fedora also went pipewire I think 2 releases ago, but I don't know if all distros have.

But then it is broken I think (although I haven't tried it, my two computers run recent Fedora with pipewire). Here pw-jack is called without any condition (or error check). So maybe what is needed is a PR where that section is wrapped in if Util.pipewire? ... else ... like some other parts? Sounds simple... except to test it.