[web] Always display active sub thread in chat thread list

Summary: Details: https://www.notion.so/commapp/Always-show-active-thread-in-chatThreadList-on-web-1ca66a4e5fdf4acaa625b133089400d5

Test Plan: Verify that opening sub thread that user is not a member of adds this thread to displayed home chat thread list as active

Reviewers: ashoat, palys-swm

Reviewed By: ashoat

Subscribers: zrebcu411, Adrian, atul, subnub, karol-bisztyga

Differential Revision: https://phabricator.ashoat.com/D691