T3047
Depends on D13486
pendingAliases are currently only removed on 'confirmed tx' websocket msgs. If the app misses these msgs, the txs are never removed.
websockets disconnect and reconnect frequently so there will be missed msgs. The app must be designed to be robust to this condition.
Right now, the 'on block found' method is. It doesn't matter how many blocks are missed, as soon as one is found the app will catch up to the current state of the blockchain. So, this diff introduces a method to remove pendingAliases that are found confirmed in the on block method.