Check permision options in D2L files

Check what D2L features might revoke access to files for instructors/students.

### Hide from Users

Using `Hide from Users` directly on the file in the table of contents **disables access to the file for students**.


Start by reviewing the D2L Table of Contents behavior described in the issue, especially the “Hide from Users” option and its effect on student file access. Investigate other D2L permission features that may revoke access for instructors or students, then document the relevant options and their effects.

Written by the indexing model from the issue text.