qml: Add ActivityListModel property to WalletQmlController

Author: johnny9

src/qml/models/walletqmlmodel.h

@@ -20,6 +20,7 @@ class WalletQmlModel : public QObject
     Q_OBJECT
     Q_PROPERTY(QString name READ name NOTIFY nameChanged)
     Q_PROPERTY(QString balance READ balance NOTIFY balanceChanged)
+    Q_PROPERTY(ActivityListModel* activityListModel READ activityListModel CONSTANT)
 
 public:
     WalletQmlModel(std::unique_ptr<interfaces::Wallet> wallet, QObject *parent = nullptr);