[web] Display more sidebars in modal

Summary: Last step of creating new modal: display sidebars inside

Test Plan: Checked if sidebars are displayed correctly, if clicking on them hides modal and changes active thread

Reviewers: ashoat, palys-swm

Reviewed By: ashoat

Subscribers: zrebcu411, Adrian

Differential Revision: https://phabricator.ashoat.com/D506