[API] API access to enable Canvas for Elementary

[jacob_standish]

Problem statement:

We would like API access to toggle the Canvas for Elementary setting for a sub-account. Instance with hundreds of sub-account could benefit from the ability to read and write to this endpoint in order to ensure settings are correct district-wide.

Proposed solution:

Add a "canvas_for_elementary" parameter when calling to /api/v1/accounts/:account_id/settings

User role(s):

admin

[AlexisNast]

This idea has been added to a theme for further consideration.