fix blinking menu at page refresh on mobile

ot_templating/Resources/Private/Partials/Modern/Menu.html

@@ -45,7 +45,7 @@
                                     classActive="active"
                                     pageUid="{ot:rootPage.getId()}">
 
-                                <ul class="menu-links">
+                                <ul class="menu-links" style="display: none;">
 
                                     <f:for each="{mainMenu}" as="mainMenuItem">
                                         <li class="hoverTrigger {mainMenuItem.class}">