test: sip: Don't use DNS lookups
Otherwise build servers might not be happy.
See f.e. https://salsa.debian.org/DebianOnMobile-team/gnome-calls/-/jobs/1600668#L633
Otherwise build servers might not be happy.
See f.e. https://salsa.debian.org/DebianOnMobile-team/gnome-calls/-/jobs/1600668#L633