Fix carousel not working when item is deleted or no items at all

web/src/app/js/carousel.js

@@ -21,6 +21,11 @@ app.carousel = {
 		const elements = mod._elements();
 		const current = elements[mod._current];
 		const next = elements[i];
+		if (next === undefined) {
+			if (i > 0)
+				return app.carousel.set(mod, 0);
+			return false;
+		}
 		var direction = 'none';
 		if (i > mod._current)
 			direction = 'right';