counters fixes

schema.graphql

@@ -412,6 +412,7 @@ type Stat {
   viewed: Int
   reacted: Int
   rating: Int
+  commented: Int
   bookmarked: Int
 }
 
@@ -440,6 +441,7 @@ type TopicStat {
   authors: Int!
   viewed: Int!
   reacted: Int!
+  commented: Int
   rating: Int
 }