Optimize log when rootcoord goroutine quit (#23698)

Signed-off-by: longjiquan <jiquan.long@zilliz.com>

internal/rootcoord/root_coord.go

@@ -220,6 +220,7 @@ func (c *Core) startTimeTickLoop() {
 	for {
 		select {
 		case <-c.ctx.Done():
+			log.Info("rootcoord's timetick loop quit!")
 			return
 		case <-ticker.C:
 			c.sendMinDdlTsAsTt()
@@ -244,6 +245,7 @@ func (c *Core) tsLoop() {
 			metrics.RootCoordTimestampSaved.Set(float64(ts.Unix()))
 
 		case <-ctx.Done():
+			log.Info("rootcoord's ts loop quit!")
 			return
 		}
 	}