fix null location bug

fixes PS-1560
fixes CNVS-13221

test plan:
  1. create a calendar event from the ui dialog
     without a location
  2. vaidate once the event is created and you click
     on it that the location is not shown as null

Change-Id: Ib2946f62fd570d4f8f9bd097e04630fce26e154c
Reviewed-on: https://gerrit.instructure.com/35261
Reviewed-by: Dave Jungst <dave@instructure.com>
QA-Review: Adam Phillipps <adam@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: Jake Sorce <jake@instructure.com>