Export all scritable contents for VirtualKeyboardDBus

Instead of only the signals, which ends up not exporting the new
willShowOnActive method.

src/virtualkeyboard_dbus.cpp

@@ -18,7 +18,7 @@ VirtualKeyboardDBus::VirtualKeyboardDBus(InputMethod *parent)
 {
     QDBusConnection::sessionBus().registerObject(QStringLiteral("/VirtualKeyboard"), this,
                                                  QDBusConnection::ExportAllProperties |
-                                                 QDBusConnection::ExportScriptableSignals | //qdbuscpp2xml doesn't support yet properties with NOTIFY
+                                                 QDBusConnection::ExportScriptableContents | //qdbuscpp2xml doesn't support yet properties with NOTIFY
                                                  QDBusConnection::ExportAllSlots);
     connect(parent, &InputMethod::activeChanged, this, &VirtualKeyboardDBus::activeChanged);
     connect(parent, &InputMethod::enabledChanged, this, &VirtualKeyboardDBus::enabledChanged);