luci-app-firewall: fix the IPv6 forwards/snats view

* corrects the view as IPv4 and IPv6 for rules where the family is 'any' and the IP not set (this fixes #9c55500f

), e.g. a forward rule like that:

config redirect 'adblock_lan53'
	option name 'Adblock DNS (lan, 53)'
	option src 'lan'
	option proto 'tcp udp'
	option src_dport '53'
	option dest_port '53'
	option target 'DNAT'
	option family 'any'

Signed-off-by: Dirk Brenken <dev@brenken.org>