DNSSD based queries fail to provide TTL

On macOS (where DNSSD is being used by default), queries such as:

```
let resolver = try AsyncDNSResolver()
let out = try await resolver.queryAAAA(name: "iadsdk.apple.com.akadns.net")
print("\(out)")
```

fail to provide the TTL:

```
[AAAARecord(address=2a02:26f0:5d00:f91::12c5, ttl=), AAAARecord(address=2a02:26f0:5d00:f9b::12c5, ttl=)]
```

Despite the fact TTL is certainly available:

```
$ dig AAAA iadsdk.apple.com.akadns.net
...
e4805.dsca.akamaiedge.net. 3 IN AAAA 2a02:26f0:5d00:f9b::12c5
↑
TTL
...
```

The TTL is available, if the c-ares underlying implementation is used:

```
let resolver = try AsyncDNSResolver(CAresDNSResolver())
let out = try await resolver.queryAAAA(name: "e4805.dsca.akamaiedge.net")
print("\(out)")
```
results in:

```
[AAAARecord(address=2a02:26f0:5d00:f91::12c5, ttl=13), AAAARecord(address=2a02:26f0:5d00:f9b::12c5, ttl=13)]
```

Tested on: https://github.com/apple/swift-async-dns-resolver/releases/tag/0.4.0

Start with the macOS DNSSD path used by AsyncDNSResolver and reproduce the queryAAAA example for iadsdk.apple.com.akadns.net. Compare its AAAARecord output with the CAresDNSResolver result; the work is done when DNSSD-based queries populate the available TTL instead of leaving it empty.

Written by the indexing model from the issue text.