Make groupColor optional even if KubeJS isn't loaded (#4684)

Author: Mqrius

src/main/java/com/gregtechceu/gtceu/api/recipe/GTRecipeSerializer.java

@@ -208,7 +208,7 @@ private static Codec<GTRecipe> makeCodec(boolean isKubeLoaded) {
                             CompoundTag.CODEC.optionalFieldOf("data", new CompoundTag()).forGetter(val -> val.data),
                             ExtraCodecs.NON_NEGATIVE_INT.fieldOf("duration").forGetter(val -> val.duration),
                             GTRegistries.RECIPE_CATEGORIES.codec().optionalFieldOf("category", GTRecipeCategory.DEFAULT).forGetter(val -> val.recipeCategory),
-                            Codec.INT.fieldOf("groupColor").forGetter(val -> val.groupColor))
+                            Codec.INT.optionalFieldOf("groupColor", -1).forGetter(val -> val.groupColor))
                     .apply(instance, (type,
                                       inputs, outputs, tickInputs, tickOutputs,
                                       inputChanceLogics, outputChanceLogics, tickInputChanceLogics, tickOutputChanceLogics,