gui: Fix duplicate wallet showing up

The slot BitcoinGUI::addWallet can be invoked twice for the same
WalletModel due to a concurrent wallet being loaded after the first `connect()`:

```cpp
 connect(wallet_controller, &WalletController::walletAdded, this, &BitcoinGUI::addWallet);
 connect(wallet_controller, &WalletController::walletRemoved, this, &BitcoinGUI::removeWallet);

 for (WalletModel* wallet_model : m_wallet_controller->getOpenWallets()) {
     addWallet(wallet_model);
```

1 files changed, 1 insertions, 1 deletions

diff --git a/src/qt/bitcoingui.cpp b/src/qt/bitcoingui.cpp
index 2aeba6d82c..bbf1faa13c 100644
--- a/src/qt/bitcoingui.cpp
+++ b/src/qt/bitcoingui.cpp
@@ -632,10 +632,10 @@ void BitcoinGUI::setWalletController(WalletController* wallet_controller)
 void BitcoinGUI::addWallet(WalletModel* walletModel)
 {
     if (!walletFrame) return;
+    if (!walletFrame->addWallet(walletModel)) return;
     const QString display_name = walletModel->getDisplayName();
     setWalletActionsEnabled(true);
     rpcConsole->addWallet(walletModel);
-    walletFrame->addWallet(walletModel);
     m_wallet_selector->addItem(display_name, QVariant::fromValue(walletModel));
     if (m_wallet_selector->count() == 2) {
         m_wallet_selector_label_action->setVisible(true);