[web] hide danger zone if usingCommServicesAccessToken

Summary: A user may delete their Comm account using their primary device. Their primary device cannot be a web device at this time, so we should just hide the Danger Zone from web users

Test Plan: Ran web with usingCSAT = true and confirmed that the Danger Zone doesn't appear in the settings list. If a user still somehow navigates to settings/danger-zone/, the component will be null so the delete account button will not appear.

Reviewers: ashoat

Reviewed By: ashoat

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D12291