Metrics for shared channels (#26199)

* add metrics definitions for shared channels

server/einterfaces/metrics.go

@@ -79,6 +79,14 @@ type MetricsInterface interface {
 	ObserveRemoteClusterClockSkew(remoteID string, skew float64)
 	IncrementRemoteClusterConnStateChangeCounter(remoteID string, online bool)
 
+	IncrementSharedChannelsSyncCounter(remoteID string)
+	ObserveSharedChannelsTaskInQueueDuration(elapsed float64)
+	ObserveSharedChannelsQueueSize(size int64)
+	ObserveSharedChannelsSyncCollectionDuration(remoteID string, elapsed float64)
+	ObserveSharedChannelsSyncSendDuration(remoteID string, elapsed float64)
+	ObserveSharedChannelsSyncCollectionStepDuration(remoteID string, step string, elapsed float64)
+	ObserveSharedChannelsSyncSendStepDuration(remoteID string, step string, elapsed float64)
+
 	IncrementJobActive(jobType string)
 	DecrementJobActive(jobType string)