Skip dead entities in getEntity(UUID) API

Spigot-Server-Patches/Add-getEntity-by-UUID-API.patch

@@ -18,7 +18,7 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +        Entity entity;
 +        for (WorldServer world : worldServer) {
 +            entity = world.getEntity(uuid);
-+            if (entity != null) {
++            if (entity != null && !entity.dead) {
 +                return entity;
 +            }
 +        }