Fix a legal metric query adoption bug. (#6270)

CHANGES.md

@@ -79,6 +79,7 @@ Release Notes.
 * Add the text analyzer for querying log in the es storage.
 * Chore:  Remove duplicate codes in Envoy ALS handler.
 * Remove the strict rule of OAL disable statement parameter.
+* Fix a legal metric query adoption bug. Don't support global level metric query.
 
 #### UI
 * Fix un-removed tags in trace query.

oap-server/server-query-plugin/query-graphql-plugin/src/main/java/org/apache/skywalking/oap/query/graphql/resolver/MetricQuery.java

@@ -58,6 +58,7 @@ public class MetricQuery implements GraphQLQueryResolver {
             condition.setEntity(new MockEntity(null));
 
             kv.setValue(query.readMetricsValue(condition, duration));
+            values.addKVInt(kv);
         } else {
             for (final String id : metrics.getIds()) {
                 KVInt kv = new KVInt();