Sidebar service doesn't update correctly over multiple pages

[Malorn44]

Describe the bug
The sidebar service doesn't properly update the sidebar (visually) across multiple open instances of yacs. For example, if you remove a course from the sidebar in one tab, it shows as unselected in the other tab but doesn't remove from the sidebar until a refresh. If you were to select a new course, it would show in the sidebar in one tab but not on the sidebar of the other tab (until a refresh).

To Reproduce
Have at least two yacs tabs open viewing the sidebar.
Select a new course that is not in the sidebar and you will see that it will show in one but not the other.
Remove a course that is in both sidebars. It will be removed in one sidebar but will only show as unselected in the other.

Expected behavior
The sidebars should be synced across multiple instances