fix username & password config in dubbo:registry (apache#5075)

Author: zhaoyuguang

dubbo-config/dubbo-config-api/src/main/java/org/apache/dubbo/config/AbstractInterfaceConfig.java

@@ -624,6 +624,8 @@ private void useRegistryForConfigIfNecessary() {
                 cc.getParameters().put(org.apache.dubbo.remoting.Constants.CLIENT_KEY,rc.getClient());
                 cc.setProtocol(rc.getProtocol());
                 cc.setAddress(rc.getAddress());
+                cc.setUsername(rc.getUsername());
+                cc.setPassword(rc.getPassword());
                 cc.setHighestPriority(false);
                 setConfigCenter(cc);
                 startConfigCenter();