refactor: simplify navigation lock

apps/client/src/common/components/navigation-menu/ViewLockedIcon.tsx

@@ -1,6 +1,7 @@
 import { IoLockClosedOutline } from '@react-icons/all-files/io5/IoLockClosedOutline';
 
 import { useFadeOutOnInactivity } from '../../../common/hooks/useFadeOutOnInactivity';
+import { cx } from '../../utils/styleUtils';
 
 import style from './NavigationMenu.module.scss';
 
@@ -8,8 +9,8 @@ export default function ViewLockedIcon() {
   const isLockIconShown = useFadeOutOnInactivity();
 
   return (
-    <div className={`${style.buttonContainer} ${!isLockIconShown ? style.hidden : ''}`}>
-      <IoLockClosedOutline className={style.lockIcon} />
+    <div className={cx([style.fadeable, style.lockIcon, !isLockIconShown && style.hidden])}>
+      <IoLockClosedOutline />
     </div>
   );
 }