FIX: Issue with incorrect heights when cloaking plugin content in posts

We noticed this with the house ads plugin. It inserted content after a
post, which was not taken into account when calculating and memoizing
the height of the element.

Co-authored-by: nlalonde
Co-authored-by: pmusaraj

app/assets/javascripts/discourse/widgets/post-stream.js.es6

@@ -34,7 +34,7 @@ export function cloak(post, component) {
     return;
   }
 
-  const $post = $(`#post_${post.post_number}`);
+  const $post = $(`#post_${post.post_number}`).parent();
   _cloaked[post.id] = true;
   _heights[post.id] = $post.outerHeight();