Since we don't process private messages yet, we don't
need to re-render when we receive a new private message
as it doesn't change any data related to recent_topics.
This data structure has never been one that we actually render into
the DOM; instead, its role is to support clicking into view that
contain muted streams and topics quickly.
This downgrade makes that situation much more explicit, and is also
useful refactoring to help simpify the upcoming changes in #16746.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
Aman Agrawal
Anders Kaseorg
Steve Howell