Fix 1.21 food using_converts_to handling

Fixes #4280

api/src/main/java/com/viaversion/viaversion/api/minecraft/item/data/FoodProperties1_20_5.java

@@ -28,9 +28,10 @@ import com.viaversion.viaversion.api.type.Types;
 import com.viaversion.viaversion.api.type.types.ArrayType;
 import com.viaversion.viaversion.api.type.types.version.Types1_21;
 import io.netty.buffer.ByteBuf;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 public record FoodProperties1_20_5(int nutrition, float saturationModifier, boolean canAlwaysEat, float eatSeconds,
-                                   Item usingConvertsTo, FoodEffect[] possibleEffects) {
+                                   @Nullable Item usingConvertsTo, FoodEffect[] possibleEffects) {
 
     public static final Type<FoodProperties1_20_5> TYPE1_20_5 = new Type<>(FoodProperties1_20_5.class) {
         @Override

common/src/main/java/com/viaversion/viaversion/protocols/v1_21to1_21_2/rewriter/BlockItemPacketRewriter1_21_2.java

@@ -423,12 +423,20 @@ public final class BlockItemPacketRewriter1_21_2 extends StructuredItemRewriter<
         }
 
         super.handleItemToClient(connection, item);
+
+        // Handle food properties item manually here - the only protocol that has it
+        // The other way around it's handled by the super handleItemToServer method
+        final StructuredDataContainer data = item.dataContainer();
+        final FoodProperties1_20_5 food = data.get(StructuredDataKey.FOOD1_21);
+        if (food != null && food.usingConvertsTo() != null) {
+            this.handleItemToClient(connection, food.usingConvertsTo());
+        }
+
         updateItemData(item);
 
         // Add data components to fix issues in older protocols
         appendItemDataFixComponents(connection, item);
 
-        final StructuredDataContainer data = item.dataContainer();
         final Enchantments enchantments = data.get(StructuredDataKey.ENCHANTMENTS);
         if (enchantments != null && enchantments.size() != 0) {
             // Level 0 is no longer allowed