fix apps menu not closing when the window is hidden, and make group folders menu...

fix apps menu not closing when the window is hidden, and make group folders menu work again

this change resolves this ReferenceError when the window is being closed:
```
2025-01-08 10:56:40:389 [ warning default qrc:/qml/src/gui/tray/MainWindow.qml:100 ]:   qrc:/qml/src/gui/tray/MainWindow.qml:100: ReferenceError: appsMenu is not defined
```

I also noticed that the "Open local or group folders" dropdown menu
wouldn't show up due to this error:
```
2025-01-08 10:56:23:327 [ warning default qrc:/qml/src/gui/tray/TrayFoldersMenuButton.qml:33 ]: qrc:/qml/src/gui/tray/TrayFoldersMenuButton.qml:33: Error: Cannot call method QQuickPopup::open on QQuickLoader_QML_48(0x5569fb4648d0)
```
--> wrapped the calls to the open/close methods in a closure

Signed-off-by: Jyrki Gadinger <nilsding@nilsding.org>