Reflect language and color scheme changes in global config in manager and all its VMs

src/qt/qt_vmmanager_main.hpp

@@ -70,6 +70,7 @@ public slots:
     void shutdownForceButtonPressed() const;
     void searchSystems(const QString &text) const;
     void newMachineWizard();
+    void updateGlobalSettings();
     void deleteSystem(VMManagerSystem *sysconfig);
     void addNewSystem(const QString &name, const QString &dir, const QString &displayName = QString(), const QString &configFile = {});
 #if __GNUC__ >= 11