Fix RPCConsole wallet selection

If a user opens multiple wallets in the GUI from the
menu bar, the last one opened is the active one in
the main window. However, For the RPC Console window,
the  _first_ one opened is active. This can be
confusing, as wallet RPC commands may be sent to a
wallet the user didn't intend.

This commit makes the RPC Console switch to the wallet
opened from the menu bar.

src/qt/rpcconsole.cpp

@@ -798,6 +798,12 @@ void RPCConsole::removeWallet(WalletModel * const walletModel)
         ui->WalletSelectorLabel->setVisible(false);
     }
 }
+
+void RPCConsole::setCurrentWallet(WalletModel* const wallet_model)
+{
+    QVariant data = QVariant::fromValue(wallet_model);
+    ui->WalletSelector->setCurrentIndex(ui->WalletSelector->findData(data));
+}
 #endif
 
 static QString categoryClass(int category)