test plan:
- enable Canvas for Elementary feature
- "Enable as homeroom course" setting should appear
in course settings
- the setting should persist when course settings are
saved and reloaded
- the setting should persist across course copy
flag = canvas_for_elementary
closes LS-1749
Change-Id: Iacba1bd37e6dbf5536dddb3610c0e26322cc42c3
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/256875
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Reviewed-by: Nate Armstrong <narmstrong@instructure.com>
QA-Review: Nate Armstrong <narmstrong@instructure.com>
Product-Review: Jeremy Stanley <jeremy@instructure.com>