removes unnecessary js_block in calendars

test plan:
* regression test calendars

Change-Id: Ieaa5ce930d9b35e122d15711d06040b4d4f21436
Reviewed-on: https://gerrit.instructure.com/29169
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Landon Wilkins <lwilkins@instructure.com>
QA-Review: Steven Shepherd <sshepherd@instructure.com>
Product-Review: Landon Wilkins <lwilkins@instructure.com>