[web] Use EnumSettingOption components in ThreadSettingsPrivacyTab
Summary:
This is a minimally-viable first pass.
Replace the inputs in ThreadSettingsPrivacyTab with EnumSettingOptions. There is still a good bit to go with stying, but should be functionally complete.
Here's how it looks:
Depends on D4050
Test Plan: Click around, change visibility, observe that things look/behave as expected
Reviewers: palys-swm, def-au1t, benschac
Reviewed By: palys-swm
Subscribers: ashoat, Adrian, yayabosh
Differential Revision: https://phabricator.ashoat.com/D4051