[web] Move queuedChanges state up from ThreadSettingsModal to ConnectedThreadSettingsModal

Summary:
Move currentTabType state out of the inner class component state, and move it out to the wrapping "Connected" functional component.

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

Depends on D3759

Test Plan: Was able to change settings in the ThreadSettingsModal and things continued to look/work as expected.

Reviewers: def-au1t, palys-swm

Reviewed By: palys-swm

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

Differential Revision: https://phabricator.ashoat.com/D3760