[Bug] prefer_ipv4 是否有bug，影响到了纯 ipv6 解析 #812

Dnsmasq 已经将53转发到 mosdns 8338 ,并关闭了缓存
root@iStoreOS:~# nslookup 6.ipw.cn
Server:         127.0.0.1
Address:        127.0.0.1:53
Non-authoritative answer:
Non-authoritative answer:
root@iStoreOS:~# nslookup 6.ipw.cn
Server:         127.0.0.1
Address:        127.0.0.1:53
Non-authoritative answer:
Non-authoritative answer:
Name:   6.ipw.cn
Address: 2400:8905::f03c:94ff:fe1c:a95e
root@iStoreOS:~# nslookup 6.ipw.cn
Server:         127.0.0.1
Address:        127.0.0.1:53
Non-authoritative answer:
Non-authoritative answer:
root@iStoreOS:~# nslookup 6.ipw.cn
Server:         127.0.0.1
Address:        127.0.0.1:53
Non-authoritative answer:
Non-authoritative answer:
使用的配置文件
log




    
:
  level: info
  file: "/var/log/mosdns.log"
# API 入口设置
api:
  http: "0.0.0.0:8339"
include: []
plugins:
  # 转发至 DNS 服务器
  - tag: forward_local
    type: forward
    args:
      concurrent: 3
      upstreams:
        - addr: "tls://223.5.5.5"
        - addr: "tls://223.6.6.6"
        - addr: "tls://1.12.12.12"
        - addr: "tls://120.53.53.53"
  - tag: main
    type: sequence
    args:
      - matches:
        - qtype 12
        exec: reject 3
      - exec: prefer_ipv4
      - exec: $forward_local
  # 启动 udp 服务器。
  - tag: udp_server
    type: udp_server
    args:
      entry: main
      listen: ":8338"
  # 启动 tcp 服务器。
  - tag: tcp_server
    type: tcp_server
    args:
      entry: main
      listen: ":8338"
### mosdns 的 log 记录
```txt
2024-05-13 02:06:35	INFO	unpacking entry	{"tag": "cn", "length": 10701, "file": "/var/mosdns/geoip_cn.txt"}
2024-05-13 02:06:35	INFO	unpacking entry	{"tag": "cn", "length": 75261, "file": "/var/mosdns/geosite_cn.txt"}
2024-05-13 02:06:35	INFO	unpacking entry	{"tag": "geolocation-!cn", "length": 24953, "file": "/var/mosdns/geosite_geolocation-!cn.txt"}
2024-05-13T02:06:36.313Z	INFO	loading plugin	{"tag": "forward_local", "type": "forward"}
2024-05-13T02:06:36.314Z	INFO	loading plugin	{"tag": "main", "type": "sequence"}
2024-05-13T02:06:36.314Z	INFO	loading plugin	{"tag": "udp_server", "type": "udp_server"}
2024-05-13T02:06:36.315Z	INFO	udp_server	udp server started	{"addr": "[::]:8338"}
2024-05-13T02:06:36.315Z	INFO	loading plugin	{"tag": "tcp_server", "type": "tcp_server"}
2024-05-13T02:06:36.315Z	INFO	tcp_server	tcp server started	{"addr": "[::]:8338", "tls": false}
2024-05-13T02:06:36.316Z	INFO	all plugins are loaded
2024-05-13T02:06:36.316Z	INFO	starting api http server	{"addr": "0.0.0.0:8339"}