Make getEntity dead check more specific

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

@@ -21,7 +21,7 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
                  Entity entity = worldserver.getEntity(uuid);
  
 -                if (entity != null) {
-+                if (entity != null && entity.isAlive()) {
++                if (entity != null && !entity.dead) {
                      return entity;
                  }
              }