Revert "work around more ipad speedgrader json calls"

This reverts commit f1e3e09b3f8255cfbfbe0c4d880e4ca16b349384.

refs CNVS-12163

test plan: With this commit, make sure that the ipad speed grader app is
able to log in and post comments on submissions.

Change-Id: I0eec14d17c4f4d65b1a33832c1689523caa04c51
Reviewed-on: https://gerrit.instructure.com/32722
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Rob Orton <rob@instructure.com>
QA-Review: August Thornton <august@instructure.com>
Product-Review: Brian Palmer <brianp@instructure.com>