When AdaptiveStream is enabled, default the subscriber to LOW quality stream
we would want LOW instead of OFF for a couple of reasons
1. when a subscriber unsubscribes from a track, we would forget their previously defined settings
depending on client implementation, subscription on/off is kept separately from adaptive stream
So when there are no changes to desired resolution, but the user re-subscribes, we may leave stream at OFF
2. when interacting with dynacast *and* adaptive stream. If the publisher was not publishing at the
time of subscription, we might not be able to trigger adaptive stream updates on the client side
(since there aren't any video frames coming through). this will leave the stream "stuck" on off, without
a trigger to re-enable it
David Zhao
5e9221dbd8