convert wiki_pages/_content js_block to js_bundle

test plan:
* regression testing on wiki pages

Change-Id: If01be351324d3bcc99e0e3b765dacb778d5795f0
Reviewed-on: https://gerrit.instructure.com/29088
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Jon Jensen <jon@instructure.com>
QA-Review: Steven Shepherd <sshepherd@instructure.com>
Product-Review: Landon Wilkins <lwilkins@instructure.com>