[web] Move changeQueued up from ThreadSettingsModal to ConnectedThreadSettingsModal

Summary:
Move changeQueued out from inner class component to outer "Connected" functional component.

(Also refactored the logic to simplify things/avoid lodash)

As part of the work to refactor ThreadSettingsModal... specifically to turn it into a functional component

Depends on D3762

Test Plan:

1. Made changes in ThreadSettingsModal
2. Logged value of changeQueued and made sure it was as expected

Reviewers: palys-swm, def-au1t

Reviewed By: palys-swm

Subscribers: ashoat, Adrian, karol-bisztyga, benschac, yayabosh

Differential Revision: https://phabricator.ashoat.com/D3763