Filter out hidden posts from TopicViewWordpressSerializer (PR #8032)

We never need to send hidden posts to WordPress.


You’ve signed the CLA, scossar. Thank you! This pull request is ready for review.

It’s even better to filter these out at the request level :wink:

Since it’s a small change, I’ve pushed it in 2ff5592941ca567a19a792a2a4c4bef71d858277