transmission: add support for announcing both IPV4 and IPV6 address to tracker

[nicefile]

Maintainer: @danwrt
Compile tested:
Run tested:

root@wdcm:/# ubus call system board
{
        "kernel": "6.6.63",
        "hostname": "wdcm",
        "system": "ARMv7 Processor rev 1 (v7l)",
        "model": "WD MyCloud Mirror Gen 2 (BWVZ/Grand Teton)",
        "board_name": "wd,cloud-mirror-gen2",
        "rootfs_type": "squashfs",
        "release": {
                "distribution": "OpenWrt",
                "version": "SNAPSHOT",
                "revision": "r28184-ac2d278528",
                "target": "mvebu/cortexa9",
                "description": "OpenWrt SNAPSHOT r28184-ac2d278528",
                "builddate": "1732473887"
        }
}

Description:
Recent transmission versions did change announce method for ipv6
(transmission/transmission#5336 (comment))

before:

root@wdcm:~# netstat -tunlp |grep 40444
tcp        0      0 0.0.0.0:40444           0.0.0.0:*               LISTEN      9358/transmission-d
tcp        0      0 :::40444                :::*                    LISTEN      9358/transmission-d
udp        0      0 0.0.0.0:40444           0.0.0.0:*                           9358/transmission-d
udp        0      0 :::40444                :::*                                9358/transmission-d

after

root@wdcm:~# netstat -tunlp |grep 40444
tcp        0      0 0.0.0.0:40444           0.0.0.0:*               LISTEN      12087/transmission-
tcp        0      0 0000:1111:2222:3333:4444:5555:6666:7777:40444 :::*                    LISTEN      12087/transmission-
udp        0      0 0.0.0.0:40444           0.0.0.0:*                           12087/transmission-
udp        0      0 0000:1111:2222:3333:4444:5555:6666:7777:40444 :::*                                12087/transmission-

I've done practical tests using ipv4 and ipv6 tracker torrent.ubuntu.com
port open test for ipv4 and ipv6 port.tools/port-checker shows both green (after router firewall configuration)

bind_address_ipv6 "" is not accepted in /etc/config/transmission and will cause transmission-daemon fail to start

[1715173329]

cc @dangowrt