PipeWire: call pw_deinit() only when running against PipeWire 3.49+

pw_deinit() was not reetrant in old PipeWire versions and it only got
fixed with PipeWire 3.49. This is causing a crash for old Ubuntu 22.04
with PipeWire 3.48 when sharing screen multiple times.

This also moves all the PipeWire version parsing logic to pipewire_utils
from screencast_utils as it makes more sense and is used from there now.

Bug: chromium:490340738
Change-Id: I62ec7adfcba040b4ab99bf535b3f16b5e4b27c1a
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/455180
Commit-Queue: Jan Grulich <grulja@gmail.com>
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Reviewed-by: Andreas Pehrson <apehrson@mozilla.com>
Reviewed-by: Alexander Cooper <alcooper@chromium.org>
Reviewed-by: Mark Foltz <mfoltz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#47100}