Fixed an issue that would prevent the media menu from going fully transparent. (#796)

The menu-items-section box of the media menu was not transparent by
default. Usually it is fully shadowed by its child "menu-content".
The color and tint of the can be configured by the user.
However, because the menu-items-section box behind the card had a
solid color, it was impossible to configure a transparent card.

Co-authored-by: Merlin Sievers <merlin.sievers@posteo.net>
Co-authored-by: Jas Singh <jaskiratpal.singh@outlook.com>

src/scss/style/menus/media.scss

@@ -17,6 +17,7 @@
     }
 
     .menu-items-section {
+        background: none;
         border-radius: $bar-menus-card_radius;
         padding: 0em;
     }