fix: added null check for blockId

- Closes #21

Author: basdxz

src/main/java/com/falsepattern/rple/internal/RPLEDefaultValues.java

@@ -585,8 +585,11 @@ public static void registerDefaultBlockTranslucencyColors(RPLEBlockColorRegistry
         for (val blockObj : blockRegistry) {
             val block = (Block) blockObj;
             val blockId = GameRegistry.findUniqueIdentifierFor(block);
+            if (blockId == null)
+                continue;
             if (!"minecraft".equals(blockId.modId))
                 continue;
+
             val translucency = fromVanillaLightOpacity(block.getLightOpacity());
             registry.colorizeBlock(block).translucency(translucency).apply();
         }