On a resume, the signal stats will call `ParticipantLeft`. Although, it
explicity says not to send events, it could still close the stats
worker.
To handle that, we created a stats worker if needed in
`ParticipantResume` notification in this PR
(https://github.com/livekit/livekit/pull/2982), but that is not enough
as that event could happen before previous signal connection closes the
stats worker.
A new stats worker does get created when `ParticipantJoined` is called
by the new signal connection, but it does not transfer connected state.
So, when the client leaves, `ParticipantLeft` is not sent.
I am not seeing why we should not transfer connected state always given
that it is the same participant SID/session. But, I have a feeling that
I am missing some corner case. Please let me know if I am missing
something here.