SPIGOT-2957 getSeaLevel() should return the real sea level, not a hard-coded value

By: Ryan Michela <deltahat@gmail.com>

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

@@ -1226,7 +1226,7 @@ public class CraftWorld implements World {
     }
 
     public int getSeaLevel() {
-        return 64;
+        return world.K(); // PAIL: rename
     }
 
     public boolean getKeepSpawnInMemory() {