HBASE-23231 Addendum remove redundant metrics.clear in ReplicationSource

This is only a problem on master which was introduced when we merge sync replication feature branch back

Author: Apache9

hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/ReplicationSource.java

@@ -600,9 +600,6 @@ public void terminate(String reason, Exception cause, boolean clearMetrics, bool
     if (this.replicationEndpoint != null) {
       this.replicationEndpoint.stop();
     }
-    if (clearMetrics) {
-      metrics.clear();
-    }
     if (join) {
       for (ReplicationSourceShipper worker : workers) {
         Threads.shutdown(worker, this.sleepForRetries);