converts error_reporting_settings js_block into js_bundle

test plan:
* regression test error reporting settings plugin

Change-Id: I842c1355132ea3fad60393364fcf1ff8816b73d9
Reviewed-on: https://gerrit.instructure.com/29139
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Jon Jensen <jon@instructure.com>
QA-Review: August Thornton <august@instructure.com>
Product-Review: Landon Wilkins <lwilkins@instructure.com>