net/samba423: opt out from Features/fortify.mk

[...]
Checking for freebsd sendfile support : not found
sendfile support not found but it was requested !
(complete log in /wrkdirs/usr/ports/net/samba423/work/samba-4.23.4/bin/config.log)

> Script "configure" failed unexpectedly.

[...]

PR: 292392