converts context/undelete_index js_block to js_bundle

test plan:
* regression test undeleting item for context

Change-Id: I5ec6bb90fba28a8fe54cac882799c45036323f18
Reviewed-on: https://gerrit.instructure.com/29158
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Jon Jensen <jon@instructure.com>
QA-Review: Caleb Guanzon <cguanzon@instructure.com>
Product-Review: Landon Wilkins <lwilkins@instructure.com>