Fix ut for AbstractConfigTest

Author: AlbumenJ

dubbo-config/dubbo-config-api/src/test/java/org/apache/dubbo/config/AbstractConfigTest.java

@@ -416,6 +416,7 @@ public void testRefreshExternal() {
             ApplicationModel.getEnvironment().setExternalConfigMap(external);
             ApplicationModel.getEnvironment().initialize();
 
+            ApplicationModel.getEnvironment().setConfigCenterFirst(true);
             overrideConfig.refresh();
 
             Assertions.assertEquals("external://127.0.0.1:2181", overrideConfig.getAddress());
@@ -453,6 +454,7 @@ public void testRefreshById() {
 
             ConfigCenterConfig configCenter = new ConfigCenterConfig();
             overrideConfig.setConfigCenter(configCenter);
+            ApplicationModel.getEnvironment().setConfigCenterFirst(true);
             // Load configuration from  system properties -> externalConfiguration -> RegistryConfig -> dubbo.properties
             overrideConfig.refresh();