The region type isn't set yet when polling regions just after file read. As a
result, the polling state cannot be evaluated correctly, and `init()` may end
up being called without the previous required call to `on_poll_success()`.
Ensure the region type is set earlier, right at the beginning of screen
initialization after file read. This way all further area/region
referesh/re-init (confusingly called "init") logic can assume it's set.
Pull Request: https://projects.blender.org/blender/blender/pulls/131050
172e9c5b83