Split out conversations new spec

Fixes CNVS-16487

Test Plan:

Ensure tests still pass

Change-Id: If8107a47c498030de4b119db932bcf2f27ec26d1
Reviewed-on: https://gerrit.instructure.com/43457
Reviewed-by: Mark Severson <markse@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: Matthew Wheeler <mwheeler@instructure.com>
QA-Review: Matthew Wheeler <mwheeler@instructure.com>