Fixed NPE in player inventory + don't ignore the cancel state of world unloads

By: Nathan Adams <dinnerbone@dinnerbone.com>

paper-server/src/main/java/org/bukkit/craftbukkit/CraftServer.java

@@ -596,7 +596,7 @@ public final class CraftServer implements Server {
         }
 
         WorldUnloadEvent e = new WorldUnloadEvent(handle.getWorld());
-        pluginManager.callEvent(new WorldUnloadEvent(handle.getWorld()));
+        pluginManager.callEvent(e);
 
         if (e.isCancelled()) {
             return false;