Fix remaining issues

Author: kvenn

packages/graphql/lib/src/core/query_manager.dart

@@ -31,6 +31,7 @@ class QueryManager {
   }) {
     scheduler = QueryScheduler(
       queryManager: this,
+      deduplicatePollers: deduplicatePollers,
     );
   }
 

packages/graphql/lib/src/graphql_client.dart

@@ -32,6 +32,7 @@ class GraphQLClient implements GraphQLDataProxy {
           link: link,
           cache: cache,
           alwaysRebroadcast: alwaysRebroadcast,
+          deduplicatePollers: deduplicatePollers,
         );
 
   /// The default [Policies] to set for each client action

packages/graphql/lib/src/scheduler/scheduler.dart

@@ -105,7 +105,7 @@ class QueryScheduler {
     final removedQuery = registeredQueries.remove(queryId);
 
     if (removedQuery == null ||
-        removedQuery.pollInterval != null ||
+        removedQuery.pollInterval == null ||
         !_deduplicatePollers) {
       return;
     }