Revert "temporarily raise default_per_page on list courses"

This reverts commit 7dd4e4855dd37b05b86164ae0b01d5e0e36175fe.

Change-Id: I6a44be89838f539b032a18c239ee0d01b89874ac
Reviewed-on: https://gerrit.instructure.com/31210
Reviewed-by: Simon Williams <simon@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: Jacob Fugal <jacob@instructure.com>
QA-Review: Jacob Fugal <jacob@instructure.com>