Move setup issue callout to under the header
Summary: Fixes T7830. Moves the callout to sit under the main header, which resolved Differential issues and Durable Column issues, but still some extra CSS shenanigans.
Test lots of pages, Home, Dashboards, Conpherence, Durable Column, Inline Diff Replies, Mobile, Workboards, etc.
Reviewers: btrahan, epriestley
Reviewed By: epriestley
Subscribers: Korvin, epriestley
Maniphest Tasks: T7830
Differential Revision: https://secure.phabricator.com/D12466