test-listen: Use OpenSSL BIO instead of GIO library
test-listen using GIO had issues running under CI for a while. GIO is reading some desktop configuration so it's not very CI friendly.
So instead of using GIO use OpenSSL BIO. The code does not get much bigger or complicated.
This fixes CI for Fedora 39 (just released and available on docker).
This allowed to remove an old workaround for GIO in .gitlab-ci.yml (cfr commit 89edf808 "ci: Workaround an issue with GLib on Fedora 30")