gui: fix wallet list hover crash on shutdown

Author: furszy

src/qt/bitcoingui.cpp

@@ -396,6 +396,8 @@ void BitcoinGUI::createActions()
         connect(usedReceivingAddressesAction, &QAction::triggered, walletFrame, &WalletFrame::usedReceivingAddresses);
         connect(openAction, &QAction::triggered, this, &BitcoinGUI::openClicked);
         connect(m_open_wallet_menu, &QMenu::aboutToShow, [this] {
+            if (m_node.shutdownRequested()) return; // nothing to do, node is shutting down.
+
             m_open_wallet_menu->clear();
             for (const std::pair<const std::string, bool>& i : m_wallet_controller->listWalletDir()) {
                 const std::string& path = i.first;