selftests: net: sort configs

Sort config files for networking selftests. This should help us
avoid merge conflicts between net and net-next. patchwork check
will be added to prevent new issues.

Acked-by: Phil Sutter <phil@nwl.cc>
Acked-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Acked-by: Florian Westphal <fw@strlen.de>
Acked-by: Antonio Quartulli <antonio@openvpn.net>
Link: https://patch.msgid.link/20251003205736.1019673-1-kuba@kernel.org


Signed-off-by: Jakub Kicinski <kuba@kernel.org>