Previously, "delete" event was sent for both archiving streams
and when user lost access to a stream. So, when user lost
access to a stream, the UI was live updated like the stream
was archived, which was not correct. But now "update" event
is sent when a stream is archived, so the webapp code is
changed accordingly to live-update the UI for both cases
correctly.
As a result, some of the changes in 43932cd6aa and a29b6485d6
are reverted as "update" event is sent when archiving and "delete"
event is sent only when a user loses access to a stream as before.