The initial implementation of the unified banner made it so it was only

visible when a review request was open. Unfortunately, this hid a lot of

useful actions and information as soon as the review request was closed.

There's no reason to prevent people from publishing reviews on closed

review requests, and in fact, that can be a really useful thing when

someone sees something late.
This change makes it so the unified banner is always shown, even when

the "this change has been marked as completed" banner is also shown.

Looked at a closed review request and saw the banner.
Verified that everything looked nice:

The banners stack nicely when the page is scrolled to the top.
As the page is scrolled, the unified banner docks to the top of the

  window and the closed banner scrolls out of view.
As the file list on the diff page scrolls past, it docks into the

  unified banner as before.