selftests: netfilter: nft_queue.sh: fix warnings with socat 1.8.0.0

Updated to a more recent socat release and saw this:
 socat E xioopen_ipdgram_listen(): unknown address family 0
 socat W address is opened in read-write mode but only supports read-only

First error is avoided via pf=ipv4 option, second one via -u
(unidirectional) mode.

Signed-off-by: Florian Westphal <fw@strlen.de>
Link: https://patch.msgid.link/20241104142821.2608-1-fw@strlen.de


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