Fix bug which caused incorrect display of courses

Fixes CNVS-12854

We were not re-rendering after requesting the next
page from the API, so we were only getting the
first pages data in the courses list.

Test-Plan:
-Make sure you have more than 10 courses and have
a student/teacher enrolled in all of them
-Navigate to the "beta" conversations page
-Select only 1 course to be "active" from the
customization form in the courses pulldown, and
uncheck the rest
-In the convo homepage click all courses, and then
hover over more courses to verify that all your
courses are displaying properly
-Likewise do the same in a new conversation under
the select course pulldown

Change-Id: I5fbdb7041040322a78c59bedb5115d92a4a1f471
Reviewed-on: https://gerrit.instructure.com/34525
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Braden Anderson <banderson@instructure.com>
QA-Review: Trevor deHaan <tdehaan@instructure.com>
Product-Review: Jayce Higgins <jhiggins@instructure.com>