Don't check consumer is open in coordinator

It's already done in a decorating message handler, in
the consumer itself.

References #142

Author: acogoluegnes

src/main/java/com/rabbitmq/stream/impl/ConsumersCoordinator.java

@@ -462,7 +462,7 @@ private ClientSubscriptionsManager(
             SubscriptionTracker subscriptionTracker =
                 subscriptionTrackers.get(subscriptionId & 0xFF);
 
-            if (subscriptionTracker != null && subscriptionTracker.consumer.isOpen()) {
+            if (subscriptionTracker != null) {
               subscriptionTracker.offset = offset;
               subscriptionTracker.hasReceivedSomething = true;
               subscriptionTracker.messageHandler.handle(

src/test/java/com/rabbitmq/stream/impl/ConsumersCoordinatorTest.java

@@ -397,8 +397,6 @@ void subscribeShouldSubscribeToStreamAndDispatchMessage_UnsubscribeShouldUnsubsc
             anyMap()))
         .thenReturn(new Client.Response(Constants.RESPONSE_CODE_OK));
 
-    when(consumer.isOpen()).thenReturn(true);
-
     AtomicInteger messageHandlerCalls = new AtomicInteger();
     AtomicInteger trackingClosingCallbackCalls = new AtomicInteger();
     Runnable closingRunnable =
@@ -445,8 +443,6 @@ void subscribeShouldSubscribeToStreamAndDispatchMessageWithManySubscriptions() {
             anyMap()))
         .thenReturn(new Client.Response(Constants.RESPONSE_CODE_OK));
 
-    when(consumer.isOpen()).thenReturn(true);
-
     Map<Byte, Integer> messageHandlerCalls = new ConcurrentHashMap<>();
     List<Runnable> closingRunnables = new ArrayList<>();
     for (int i = 0; i < ConsumersCoordinator.MAX_SUBSCRIPTIONS_PER_CLIENT; i++) {