If the user has not opted in, automatically set the sidebar to `active` if:
1. The sidebar has not already been automatically set to `active` twice.
2. It's been at least 24 hours since the user last saw the sidebar because
of this auto-activation behavior.
3. The sidebar was not already auto-activated in this session. This is
unlikely to come into play for most users, since this only executes on
startup and when the `enabled` Nimbus variable changes.
Also, if the user has still not opted in at the end of the session, and
we auto-activated the sidebar for them, auto-close the sidebar on
shutdown. This means we show the onboarding to the user automatically in
each PDP for up to 2 sessions. After that, if the user still has not
opted in, we will stop trying.
Differential Revision: https://phabricator.services.mozilla.com/D184994