[FIX] website: rendering 1 preview instead of 2 in SEO dialog

Before this commit, In dialog box of Optimize SEO, we were getting 2 previews.
This fix will remove the rendering of extra preview.

Task ID:1949636

addons/website/static/src/js/menu/seo.js

@@ -342,8 +342,6 @@ var MetaTitleDescription = Widget.extend({
         this.$warning = this.$('div#website_meta_description_warning');
         this.$preview = this.$('.js_seo_preview');
 
-        this._renderPreview();
-
         if (!this.canEditTitle) {
             this.$title.attr('disabled', true);
         }