typo: portal access admin service (#5305)

docs/en/design/apollo-design.md

@@ -74,8 +74,8 @@ sequenceDiagram
   	Meta Server -->> Portal: Admin Service's instances(Multiple IP+Port)
   	loop until success
   		Portal ->> Portal: load balance choose a Admin Service instance
-  		Portal ->> Config Service: request
-  		Config Service -->> Portal: ack
+  		Portal ->> Admin Service: request
+  		Admin Service -->> Portal: ack
   	end	
   ```
 

docs/zh/design/apollo-design.md

@@ -78,8 +78,8 @@ sequenceDiagram
 	Meta Server -->> Portal: Admin Service's instances(Multiple IP+Port)
 	loop until success
 		Portal ->> Portal: load balance choose a Admin Service instance
-		Portal ->> Config Service: request
-		Config Service -->> Portal: ack
+		Portal ->> Admin Service: request
+		Admin Service -->> Portal: ack
 	end
 ```