Use the response RR type when filtering

[ainar-g]

(Split from #4230.)

Currently, when we filter a DNS response, we use the request resource record type in the filtering request. That creates issues with e.g. CNAME responses to A/AAAA queries. @ameshkov proposes using the type of the response RRs rather than the request ones.

I feel like there could be issues with misbehaving upstreams though. Like an upstream that responds with AAAA records on an A request, for example. We'll see how much of an issue that would be.

[ameshkov]

@ainar-g this is actually a simple improvement, but worthy of implementing in a patch and not waiting for v0.108.0 release (since we need the same change for AdGuard DNS).

[ainar-g]

@ameshkov, I thought about that, but I feel like this is a change in behaviour that isn't necessarily a bug fix, and I prefer to leave such changes to “major” (minor in SV) versions. In any case, nothing prevents us completing it on the main branch and then cherry-picking it into the release branch if there is an actual need for it.

I'll take AGD into account.