fix calendar event show page delete link
fix calendar event show page delete link

test plan:
* create a calendar event
* click on the title of the event on the main calendar page
 to go to the event details page
* click "delete this event"
* it should do something

closes #CNVS-31328

Change-Id: I6b17652f1189e2b496088c7181100d93f3c6b8b7
Reviewed-on: https://gerrit.instructure.com/104553
Tested-by: Jenkins
Reviewed-by: Jeremy Stanley <b3f594e10a9edcf5413cf1190121d45078c62290@instructure.com>
QA-Review: David Tan <6283e310a2278fc51bdc4fb5974f70dd9c3366b9@instructure.com>
Product-Review: James Williams  <3a5f4ed991dbfa5c9ef76ad729d240ca12f62180@instructure.com>

sfu/canvas-lms,instructure/canvas-lms,venturehive/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,venturehive/canvas-lms,sfu/canvas-lms,venturehive/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,venturehive/canvas-lms