Fix disappearing navigation arrows in fotorama zoom

Author: luukschakenraad

lib/web/fotorama/fotorama.js

@@ -2092,7 +2092,7 @@ fotoramaVersion = '4.6.4';
                 o_navTop = opts.navposition === 'top';
                 classes.remove.push(selectClass);
 
-                $arrs.toggle(opts.arrows);
+                $arrs.toggle(!!opts.arrows);
             } else {
                 o_nav = false;
                 $arrs.hide();