[Gradebook] Add Warning Message for Gradebook "Sync Grades to SIS" Feature

[jfountain]

Problem statement:

When our teachers and course designers use the "Sync" button found in the gradebook to "Sync (final) Grades to SIS," they often forget to post all the relevant grade columns first. This causes inaccurate final grades to be pushed to the SIS. They cannot always see the problem by viewing the final grade through the GUI, as they sometimes don't know what the eyeball-slash icon means.

Proposed solution:

When a user clicks the "Sync" button and selects "Sync Grades to SIS" program Canvas to check their grade columns to see if any are hidden/not posted. If any are hidden, produce a warning message stating which columns are not posted and tell the user that those grades will not be included in the final score pushed to the SIS. Allow them to go back and post the grade columns before syncing.

User role(s):

admin,instructor,ta,designer

[jfountain]

A screenshot is attached showing the button and feature I'm referring to in this idea request.