sync discussion topic content tag workflow states

fixes CNVS-11026

test plan:
 - in a course with Draft State enabled,
  - create some (unpublished) discussion topics
    and add them to a module
  - publish a discussion topic via the modules page, and
    (probably easiest in a second browser) ensure a student
    can see it in the module
  - publish a discussion topic via the discussion's own page,
    and ensure a student can see it in the module

Change-Id: Ia2887a7397fb34c9dd65903a1ce89997e01dcc92
Reviewed-on: https://gerrit.instructure.com/29802
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Bracken Mosbacker <bracken@instructure.com>
Product-Review: Bracken Mosbacker <bracken@instructure.com>
QA-Review: Nathan Rogowski <nathan@instructure.com>