remove redundant config address

dubbo-admin-backend/src/main/java/org/apache/dubbo/admin/config/ConfigCenter.java

@@ -49,7 +49,7 @@ public class ConfigCenter {
     @Value("${admin.registry.address:}")
     private String registryAddress;
 
-    @Value("${admin.metadata.address:}")
+    @Value("${admin.metadata-report.address:}")
     private String metadataAddress;
 
     @Value("${admin.registry.group:}")

dubbo-admin-backend/src/main/resources/application.properties

@@ -18,8 +18,7 @@
 # centers in dubbo2.7
 admin.registry.address=zookeeper://127.0.0.1:2181
 admin.config-center=zookeeper://127.0.0.1:2181
-admin.metadata.address=zookeeper://127.0.0.1:2181
-dubbo.configcenter="zookeeper://127.0.0.1:2181"
+admin.metadata-report.address=zookeeper://127.0.0.1:2181