Show original topic title if expanded

When a post is moderated, a message "this topic was moderated by User" is
shown & the topic children (replies) are collapsed.
When the user has sufficient permissions, he'll be able to expand the moderated
topic, which will now also show the original title text.

Mingle: 421
Change-Id: I9f55296bd4ad3f25432c8437beb33153dcfcf57f
Merge "Show original topic title if expanded"