vpn: various state management fixes

Common/SettingsData.qml

@@ -134,6 +134,7 @@ Singleton {
     property bool weatherEnabled: true
 
     property string networkPreference: "auto"
+    property string vpnLastConnected: ""
 
     property string iconTheme: "System Default"
     property var availableIconThemes: ["System Default"]
@@ -1398,6 +1399,11 @@ Singleton {
         saveSettings()
     }
 
+    function setVpnLastConnected(uuid) {
+        vpnLastConnected = uuid
+        saveSettings()
+    }
+
     function setIconTheme(themeName) {
         iconTheme = themeName
         updateGtkIconTheme(themeName)