Witness Count: Valid Witnesses

[cokes518]

The current route shows how many witnesses a Hotspot has, but does not necessarily separate valid witnesses from invalid ones.

We know that only valid witnesses contribute to earnings, so we should only relevant data to the user.

[madninja]

This is not quite possible with he current hotspot witnesses as collected by the chain. A witness for a hotspot in the result may have witnesses the hotspot multiple times, and we don't know anymore which one of those witness receipts were valid or not