We want to reuse the (previously known as) NotificationsOption component for the "Privacy" tab of ThreadSettingsModal.
As a first step, we rename NotificationsOption to more generic EnumSettingsOption (open to alternative names). In later diffs will remove "Notifications-specific" parts of EnumSettingsOption and make it more generic.
Made sure to rename component, rename file, and fix imports.
Depends on D4044