reorder content and sidebar

headers in the content should come before headers
in the sidebar

fixes CNVS-15105

Change-Id: I6ae02bd784ecf893acae6574f93685f9216f035a
Reviewed-on: https://gerrit.instructure.com/40101
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Jason Madsen <jmadsen@instructure.com>
QA-Review: Caleb Guanzon <cguanzon@instructure.com>
Product-Review: Ryan Florence <ryanf@instructure.com>