fix: don't log expected publisher data channel close as unexpected

[longcw]

Fixes the spurious ERROR logs reported in livekit/agents#6250.

When the server tears a session down (e.g. the room is deleted) it closes the publisher data channels from the remote side before the engine sets its closed flag, so the close was logged at ERROR as "publisher data channel closed unexpectedly" even though it was expected.

This records the terminal disconnect (server Leave{Disconnect}) so the close it triggers isn't logged as unexpected. Genuine unexpected closes (e.g. an oversized message silently killing the channel) still log, and Resume/Reconnect are unaffected.

[github-actions]

Changeset

The following package versions will be affected by this PR:

Package	Bump
livekit	patch
livekit-ffi	patch

[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no bugs or issues to report.

[davidzhao]

we should also set this bit when the user disconnects intentionally.. so close would have a reason of ClientInitiated.

[longcw]

we should also set this bit when the user disconnects intentionally.. so close would have a reason of ClientInitiated.

user disconnects using close() already set closed that prevents the error log

                if !inner.closed.load(Ordering::Acquire)
                    && !inner.disconnecting.load(Ordering::Acquire)
                    && inner.publisher_pc.is_connected()
                {
                    log::error!("publisher data channel '{}' closed unexpectedly", label);
                }