Volo-HTTP DnsResolver panic'd parse dns config

## Bug Report

```
{
"timestamp": "2025-03-17T00:55:31.329274Z",
"level": "ERROR",
"fields":
{
"message": "process panicked",
"panic": "panicked at /cargo/git/checkouts/volo-77ae0fff0752de6f/72f84c8/volo-http/src/client/dns.rs:68:14:\n[Volo-HTTP] DnsResolver: failed to parse dns config: ResolveError { kind: Io(Os { code: 2, kind: NotFound, message: \"No such file or directory\" }) }",
},
"target": "edge_adm_netd",
"filename": "src/main.rs",
"line_number": 79,
}
```

### Version

```
├── volo v0.10.5 (https://github.com/ii64/volo.git?branch=main#72f84c80)
├── volo-gen v0.1.0 (/xx/volo-gen)
│ ├── volo v0.10.5 (https://github.com/ii64/volo.git?branch=main#72f84c80) (*)
│ └── volo-grpc v0.10.4 (https://github.com/ii64/volo.git?branch=main#72f84c80)
│ └── volo v0.10.5 (https://github.com/ii64/volo.git?branch=main#72f84c80) (*)
│ └── volo-build v0.10.19 (https://github.com/ii64/volo.git?branch=main#72f84c80)
│ ├── volo v0.10.5 (https://github.com/ii64/volo.git?branch=main#72f84c80)
├── volo-grpc v0.10.4 (https://github.com/ii64/volo.git?branch=main#72f84c80) (*)
└── volo-http v0.3.1 (https://github.com/ii64/volo.git?branch=main#72f84c80)
└── volo v0.10.5 (https://github.com/ii64/volo.git?branch=main#72f84c80) (*)
```

### Platform

```
aarch64-linux-android
```

### Crates

### Description