Fix sea level not being available on client, move hook to Dimension

src/main/java/net/minecraftforge/common/extensions/IForgeDimension.java

@@ -22,11 +22,9 @@ package net.minecraftforge.common.extensions;
 import javax.annotation.Nullable;
 
 import net.minecraft.client.audio.MusicTicker;
-import net.minecraft.entity.Entity;
 import net.minecraft.entity.player.PlayerEntity;
 import net.minecraft.entity.player.ServerPlayerEntity;
 import net.minecraft.util.math.BlockPos;
-import net.minecraft.util.math.MathHelper;
 import net.minecraft.util.math.Vec3d;
 import net.minecraft.world.World;
 import net.minecraft.world.biome.Biome;
@@ -34,7 +32,6 @@ import net.minecraft.world.chunk.Chunk;
 import net.minecraft.world.dimension.Dimension;
 import net.minecraft.world.dimension.DimensionType;
 import net.minecraft.world.dimension.NetherDimension;
-import net.minecraft.world.dimension.OverworldDimension;
 import net.minecraft.world.storage.WorldInfo;
 import net.minecraftforge.api.distmarker.Dist;
 import net.minecraftforge.api.distmarker.OnlyIn;
@@ -278,6 +275,11 @@ public interface IForgeDimension
     {
         return getWorld().getWorldInfo().getGenerator().getHorizon(getWorld());
     }
+    
+    default int getSeaLevel()
+    {
+        return 63;
+    }
 
     /**
      * Determine if the cursor on the map should 'spin' when rendered, like it does for the player in the nether.