[stable15] prevent the server's app-navigation's css to overru… (#16937)

[stable15] prevent the server's app-navigation's css to overrule the scoped css …

core/css/apps.scss

@@ -77,7 +77,7 @@ kbd {
 
 /* APP-NAVIGATION ------------------------------------------------------------ */
 /* Navigation: folder like structure */
-#app-navigation {
+#app-navigation:not(.vue) {
 	width: $navigation-width;
 	position: fixed;
 	top: $header-height;