fix: select always online peers for remote listing (#11153)

always find the right set of online peers for remote listing,
this may have an effect on listing if the server is down - we
should do this to avoid always performing transient operations
on bucket->peerClient that is permanently or down for a long
period.

cmd/peer-rest-client.go

@@ -78,6 +78,11 @@ func (client *peerRESTClient) String() string {
 	return client.host.String()
 }
 
+// IsOnline returns true if the peer client is online.
+func (client *peerRESTClient) IsOnline() bool {
+	return client.restClient.IsOnline()
+}
+
 // Close - marks the client as closed.
 func (client *peerRESTClient) Close() error {
 	client.restClient.Close()