fix(settings): connect enable LAN discovery checkbox

Checkbox and setting introduced in 9f8b0fed07 but not connected.

src/widget/form/settings/advancedform.cpp

@@ -180,6 +180,11 @@ void AdvancedForm::on_cbEnableUDP_stateChanged()
     bodyUI->cbEnableLanDiscovery->setEnabled(enableUdp);
 }
 
+void AdvancedForm::on_cbEnableLanDiscovery_stateChanged()
+{
+    Settings::getInstance().setEnableLanDiscovery(bodyUI->cbEnableLanDiscovery->isChecked());
+}
+
 void AdvancedForm::on_proxyAddr_editingFinished()
 {
     Settings::getInstance().setProxyAddr(bodyUI->proxyAddr->text());

src/widget/form/settings/advancedform.h

@@ -49,6 +49,7 @@ private slots:
     // Connection
     void on_cbEnableIPv6_stateChanged();
     void on_cbEnableUDP_stateChanged();
+    void on_cbEnableLanDiscovery_stateChanged();
     void on_proxyAddr_editingFinished();
     void on_proxyPort_valueChanged(int port);
     void on_proxyType_currentIndexChanged(int index);