gui: Avoid redundant tx status updates

In TransactionTablePriv::index, avoid calling
interfaces::Wallet::tryGetTxStatus if the status is up to date as of the most
recent NotifyBlockTip notification.  Store height from the most recent
notification in a new ClientModel::cachedNumBlocks variable in order to check
this.

This avoids floods of IPC traffic from tryGetTxStatus with #10102 when there
are a lot of transactions. It might also make the GUI a little more efficient
even when there is no IPC.

src/qt/walletmodel.cpp

@@ -9,6 +9,7 @@
 #include <qt/walletmodel.h>
 
 #include <qt/addresstablemodel.h>
+#include <qt/clientmodel.h>
 #include <qt/guiconstants.h>
 #include <qt/optionsmodel.h>
 #include <qt/paymentserver.h>
@@ -32,8 +33,13 @@
 #include <QTimer>
 
 
-WalletModel::WalletModel(std::unique_ptr<interfaces::Wallet> wallet, interfaces::Node& node, const PlatformStyle *platformStyle, OptionsModel *_optionsModel, QObject *parent) :
-    QObject(parent), m_wallet(std::move(wallet)), m_node(node), optionsModel(_optionsModel), addressTableModel(nullptr),
+WalletModel::WalletModel(std::unique_ptr<interfaces::Wallet> wallet, ClientModel& client_model, const PlatformStyle *platformStyle, QObject *parent) :
+    QObject(parent),
+    m_wallet(std::move(wallet)),
+    m_client_model(client_model),
+    m_node(client_model.node()),
+    optionsModel(client_model.getOptionsModel()),
+    addressTableModel(nullptr),
     transactionTableModel(nullptr),
     recentRequestsTableModel(nullptr),
     cachedEncryptionStatus(Unencrypted),