fix(EditPlaylist): logged-out users shouldn't be able to drag songs around

Signed-off-by: Jonathan <theflametrooper@gmail.com>

frontend/src/components/modals/EditPlaylist/index.vue

@@ -356,7 +356,7 @@ export default {
 			return {
 				animation: 200,
 				group: "description",
-				disabled: !this.playlist.isUserModifiable,
+				disabled: !this.isEditable(),
 				ghostClass: "draggable-list-ghost"
 			};
 		}