[FIX] website: restore blog & event cover properties options editing

Changing the filter color and its intensity was not working anymore
because of failed JS refactoring when the logic was shared for both
blog posts and events in website.

closes odoo#40217

Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>

addons/website/static/src/js/editor/snippets.options.js

@@ -1788,12 +1788,12 @@ options.registry.CoverProperties = options.Class.extend({
         this.$filterColorOpts.removeClass('active');
 
         var activeFilterValue = this.$filterValueOpts
-            .filter(el => {
+            .filter((i, el) => {
                 return (parseFloat($(el).data('filterValue')).toFixed(1) === parseFloat(this.$filter.css('opacity')).toFixed(1));
             }).addClass('active').data('filterValue');
 
         var activeFilterColor = this.$filterColorOpts
-            .filter(el => {
+            .filter((i, el) => {
                 return this.$filter.hasClass($(el).data('filterColor'));
             }).addClass('active').data('filterColor');