Disconnect bridge users from their accounts on logout. This does not
actually delete the Signal device being logged out of, though.

Pass it a context, and call it in fnDeleteSession

Treat a failure to delete the device from the store as fatal, because
otherwise credentials would remain in the store & might be reused
accidentally on the next read from the store (like on bridge restart).

as the condition for this response has false positives

Make logouts delete the device from the database (not just clear
sessions and keys) and update the users store & user-to-uuid map.