Hide Pages if Hidden

Seems self-evident, but [this thread](https://help.instructure.com/entries/21422345) on the Canvas Communities highlights an annoying visibility issue: users who can't see the Pages section can still see the whole list of pages if they are on a Page.

This removes those lists from the interface.

Signed-off-by: Seth Battis <SethBattis@stmarksschool.org>