Improve "domain verification" speed by querying the authoritative nameservers
Proposal
As documented in the handbook:
If a "negative lookup" has been cached, it will be for a time specified by the MINIMUM field of the SOA record.
TXT records containing the incorrect code will be cached for a time specified by the TXT record's TTL field.
This can take hours depending on the SOA MINIMUM field and TXT record's TTL. The code should just query the authoritative nameservers, so we can avoid waiting for the cache to expire for hours.