Proxy doesn't pass target response status codes through

[tanyav2]

Let's assume a query contains a bad key ID. The client will expect to see a 401 response, which is indeed what happens when there is no proxy present:

resp: Response { url: "https://odoh.cloudflare-dns.com/dns-query", status: 401, headers: {"date": "Thu, 03 Dec 2020 ....} }

When a proxy is running, the client instead sees a 200 status code, which makes it much harder for them to accurately flag the issue they are running into:

resp: Response { url: "https://odoh1.surfdomeinen.nl/proxy?targethost=odoh.cloudflare-dns.com&targetpath=%2Fdns-query", status: 200, headers: {"content-length": "0" ...} }