[web] Mark inbox icon as active when necessary

Summary:
When we're in chat, calendar or apps, we should mark the icon with purple rectangle.
https://www.figma.com/file/a1nkbWgbgjRlrOY9LVurTz/Comm-%2F-Desktop-app?node-id=1170%3A77595

Depends on D4144

Test Plan: Check if the icon is marked while on apps, chat or calendar. It shouldn't be marked while on settings page.

Reviewers: def-au1t, atul, benschac

Reviewed By: atul

Subscribers: ashoat, Adrian, yayabosh

Differential Revision: https://phabricator.ashoat.com/D4145