[web] Display friend list buttons in the modal

Summary:
Display the buttons depending on relationship status.

Depends on D3676

Test Plan: Render a couple of rows for users with different relationship statuses (friend, request sent, request received) and check if correct buttons are rendered.

Reviewers: benschac, atul, def-au1t

Reviewed By: benschac, atul

Subscribers: ashoat, Adrian, karol-bisztyga, yayabosh

Differential Revision: https://phabricator.ashoat.com/D3677