This commit provides a few fixes for the non-fullscreen view:
* remove the subquiz link on slides of type 'quiz' in the sidebar;
* hide completion icons in sidebar if not member;
* only show the 'embed on your website' option when a slide has an embed
code. This will prevent slides of type 'certification' or 'quiz' to
display an empty embed box;
Commit linked to task ID 1941250 and PR #31977