[web] [feat] add unread dot

Summary:
add unread dot per figma screen shot

Ignore title color, will fix in a follow up diff.

Test Plan: match figma

Reviewers: atul, ashoat

Reviewed By: atul, ashoat

Subscribers: ashoat, palys-swm, Adrian, karol-bisztyga

Differential Revision: https://phabricator.ashoat.com/D3185