[grid] Filter out reserved sessions while displaying in Grid UI. Display the ones with an actual session id only.

Author: pujagani

java/src/org/openqa/selenium/grid/graphql/Grid.java

@@ -28,6 +28,7 @@
 import org.openqa.selenium.grid.sessionqueue.NewSessionQueue;
 import org.openqa.selenium.internal.Require;
 import org.openqa.selenium.json.Json;
+import org.openqa.selenium.remote.SessionId;
 
 import java.net.URI;
 import java.util.ArrayList;
@@ -41,6 +42,7 @@
 public class Grid {
 
   private static final Json JSON = new Json();
+  private static final SessionId RESERVED = new SessionId("reserved");
   private final URI uri;
   private final DistributorStatus distributorStatus;
   private final List<Set<Capabilities>> queueInfoList;
@@ -150,7 +152,7 @@ public List<Session> getSessions() {
     List<Session> sessions = new ArrayList<>();
     for (NodeStatus status : distributorStatus.getNodes()) {
       for (Slot slot : status.getSlots()) {
-        if (slot.getSession()!=null) {
+        if (slot.getSession() != null && !slot.getSession().getId().equals(RESERVED)) {
           org.openqa.selenium.grid.data.Session session = slot.getSession();
           sessions.add(
             new org.openqa.selenium.grid.graphql.Session(