Add a "NoIPv6Consensus" flag to consensus-health
If a relay has different ReachableIPv6 addresses, and there is a tie for the most common ReachableIPv6 address, the authorities won't add any IPv6 ORPort in the consensus.
We could label the consensus column as NoIPv6Consensus in this case, instead of leaving it blank.
If this does start happening more, it would be great to know about it. And it would also help relay operators in this situation.
(See the discussion on the metrics list.)