CLC-2949 - Update "Add People" tool to support Canvas Account Admins
CLC-2949 - Removed unnecessary option with call to Canvas::Admins#admins_list
CLC-2949 - Converted @canvas_course to method var in #authorize_adding_user. Moved canvas_course_id integer conversion to method
CLC-2949 - Added comment regarding dependency for Canvas::CoursePolicy class
CLC-2949 - Removed unnecessary exception handler in CanvasController. Inherited from ApplicationController
CLC-2949 - Removed unused functionality from Canvas::Admins
Merge pull request #2409 from redconfetti/CLC-2949-add-admin-support

CLC-2949 - Update "Add People" tool to support Canvas Account Admins