Fix Alfheim lighting engine ram usage workaround with Alfheim 1.6 (#2838)

Author: kumquat-ir

src/api/java/dev/redstudio/alfheim/lighting/LightingEngine.java

@@ -0,0 +1,5 @@
+package dev.redstudio.alfheim.lighting;
+
+// stub class to appease javac
+public class LightingEngine {
+}

src/main/java/gregtech/api/util/world/DummyWorld.java

@@ -15,6 +15,7 @@
 import net.minecraftforge.fml.common.Optional.Method;
 import net.minecraftforge.fml.relauncher.FMLLaunchHandler;
 
+import dev.redstudio.alfheim.lighting.LightingEngine;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -116,4 +117,9 @@ public int getLightFromNeighborsFor(EnumSkyBlock type, BlockPos pos) {
     public int alfheim$getLight(BlockPos pos, boolean checkNeighbors) {
         return 15;
     }
+
+    @Method(modid = Mods.Names.ALFHEIM)
+    public LightingEngine getAlfheim$lightingEngine() {
+        return null;
+    }
 }