Praefect: Update voter state on failed node RPC

Currently when a secondary node RPC fails the error is ignored and the transaction continues waiting for additional votes even if there are not enough outstanding votes to reach quorum. If quorum becomes impossible, due to the failed node, the transaction hangs until the context gets canceled. This is not desirable as ideally once it has been established that there is not enough outstanding votes to reach the required threshold specified by the transaction, the transaction should be canceled. This change adapts the ErrHandler function of the secondary nodes to cancel the voter in the transaction associated with the failed RPC. In this process the voter's result state is updated to VoteCanceled and the subtransaction is checked to see if quorum can still be achieved. If quorum is impossible the vote is failed and the voters are unblocked. If quorum is still possible the voters remain blocked waiting for further votes to decide the outcome.

Closes: #4088 (closed)