converts shared/errors js_block into js_bundle

test plan:
* regression test shared error form (for submitting errors)

Change-Id: Ief28c72f4dd488bb1cbeb795f7a050ad56bf2fe8
Reviewed-on: https://gerrit.instructure.com/29105
Reviewed-by: Jon Jensen <jon@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Jeremy Putnam <jeremyp@instructure.com>
Product-Review: Landon Wilkins <lwilkins@instructure.com>