I'm not 100% sure this fixes it, but I haven't managed to make it fail
after this change, so let's keep an eye on it during testing.

I think the fact that the mail composer is a remote view controller is
affecting the appearance system.
Merge branch 'release/3.8.4' of github.com:wordpress-mobile/WordPress-iOS into release/3.8.4
Better handling of DudaMobile redirects