Allow to retry nodes on Boss events

Szamsziel

For a new player without a strong deck killing the second or last boss in Avacyn-like events is not possible. As so I'd like to have an option to restart the node - keeping charges but starting with 1St boss. In the competitive terms it would not affect finals because the amount of ribbons for the bosses differs.

gulgoth

I feel like the only fair way to implement this would be if it was only an option after losing or if it cost you 1 charge to do so. Only the final node is worth more points. Since optional objectives are different people could abuse this to just replay the first/easiest node

Szamsziel

Just calculate ribbons available per node. So going for easiest will be less rewarding.