exclude sip client from track publish metric (#3007)

pkg/rtc/participant.go

@@ -2133,7 +2133,13 @@ func (p *ParticipantImpl) mediaTrackReceived(track *webrtc.TrackRemote, rtpRecei
 				"track", logger.Proto(mt.ToProto()),
 				"cost", pubTime.Milliseconds(),
 			)
-			prometheus.RecordPublishTime(mt.Source(), mt.Kind(), pubTime)
+
+			// SIP client relies on the remote peer's media packet to publish the track and
+			// sometimes it costs 10s to arrive after handshake.
+			// So we ignore the publish time for SIP client to avoid the high value in the metrics.
+			if p.Kind() != livekit.ParticipantInfo_SIP {
+				prometheus.RecordPublishTime(mt.Source(), mt.Kind(), pubTime)
+			}
 			p.handleTrackPublished(mt)
 		}()
 	}