[FIX] website: video snippet size detection

addons/website/static/src/js/website.snippets.animation.js

@@ -180,7 +180,7 @@
     website.snippet.animationRegistry.media_video = website.snippet.Animation.extend({
         selector: ".media_iframe_video",
         start: function () {
-            if (!this.$target.has('.media_iframe_video_size')) {
+            if (!this.$target.has('.media_iframe_video_size').length) {
                 var editor = '<div class="css_editable_mode_display">&nbsp;</div>';
                 var size = '<div class="media_iframe_video_size">&nbsp;</div>';
                 this.$target.html(editor+size+'<iframe src="'+_.escape(this.$target.data("src"))+'" frameborder="0" allowfullscreen="allowfullscreen"></iframe>');