Fix OpenGraph/LinkedData embeds having incorrectly-generated iframes (#16978)

app/lib/link_details_extractor.rb

@@ -91,7 +91,7 @@ class LinkDetailsExtractor
   end
 
   def html
-    player_url.present? ? content_tag(:iframe, src: player_url, width: width, height: height, allowtransparency: 'true', scrolling: 'no', frameborder: '0') : nil
+    player_url.present? ? content_tag(:iframe, nil, src: player_url, width: width, height: height, allowtransparency: 'true', scrolling: 'no', frameborder: '0') : nil
   end
 
   def width