selftests: mptcp: shellcheck: support v0.11.0

This v0.11.0 version introduces SC2329:

  Warn when (non-escaping) functions are never invoked.

Except that, similar to SC2317, ShellCheck is currently unable to figure
out functions that are invoked via trap, or indirectly, when calling
functions via variables. It is then needed to disable this new SC2329.

Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250908-net-mptcp-misc-fixes-6-17-rc5-v1-3-5f2168a66079@kernel.org


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