When importing a watch-only address over `importmulti` with a specific timestamp, the wallet's `nTimeFirstKey` will be set to 1.
I think we should add a optional timestamp to `CWallet::AddWatchOnly()` and use it when importing addresses or pubkeys.

{
                CWalletTx &coin = mapWallet[txin.prevout.hash];
                coin.BindWallet(this);
                NotifyTransactionChanged(this, coin.GetHash(), CT_UPDATED);
            }
        }
        
        mapRequestCount[wtxNew.GetHash()] = 0;
        if (fBroadcastTransactions)
        {
            
            if (!wtxNew.AcceptToMemoryPool(maxTxFee, state)) {
                LogPrintf("CommitTransaction(): Transaction cannot be broadcast immediately, %s\n", state.GetRejectReason());
                
            } else {
                wtxNew.RelayWalletTransaction(connman);
            }
        }
    }
    return true;
}
void CWallet::ListAccountCreditDebit(const std::string& strAccount, std::list<CAccountingEntry>& entries) {