Add required prop to fix spec warning.
Add required prop to fix spec warning.

Test Plan:
:qa-cr:

Change-Id: I3c74a244d4188667e92323e638df086c6cdb7a4a
Reviewed-on: https://gerrit.instructure.com/173982
Tested-by: Jenkins
Reviewed-by: Neil Gupta <cc4fec8a34766005dd45d48be045c08d736c11ed@instructure.com>
QA-Review: Brian Watson <4411c2aac809443ec63e2dd517de0f2dbc7408c6@instructure.com>
Product-Review: Frank Murphy III <ed7a7068a7b39653c9ca1c429cffcb87c4a069c6@instructure.com>

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