sessionresolver: we can re-enable dns.google DoH HTTP3 resolutions

[bassosimone]

This issue is about adding again support for performing DNS resolutions over HTTP3 in the sessionresolver package of ooni/probe-cli.

We previously removed support for doing that from sessionresolver following an incident in which Google briefly stopped servicing HTTP3.

It seems now dns.google supports QUIC and HTTP3 again.

Ideally, here we should re-add to sessionresolver the lines of code that were telling it to speak DNS-over-HTTPS using QUIC and HTTP3 with dns.google. We should also test with urlgetter that the service is indeed working.

To perform this kind of testing the procedure is roughly:

• go build -v ./internal/cmd/miniooni
• ./miniooni -OHTTP3Enabled=true -OResolverURL=https://dns.google/dns-query -i dnslookup://example.com urlgetter and then we should inspect the resulting measurement to check whether it worked

Lastly, we should also double check that we did not reduce the test coverage.

See https://github.com/ooni/probe/issues/1873 for historical context.

[bassosimone]

@yeganathan18 mentioned he wanted to work on this issue! ✨

[bassosimone]

I'm in touch with @yeganathan18 to land a fix for this problem!

[bassosimone]

Issue has been solved!