1.20.5 -> 1.20.3: nullify empty tags (#3949)

Co-authored-by: AJ Ferguson <AJ-Ferguson@users.noreply.github.com>

common/src/main/java/com/viaversion/viaversion/protocols/v1_20_3to1_20_5/rewriter/BlockItemPacketRewriter1_20_5.java

@@ -408,6 +408,10 @@ public final class BlockItemPacketRewriter1_20_5 extends ItemRewriter<Clientboun
             dataConverter.writeToTag(connection, structuredData, tag);
         }
 
+        if (tag.isEmpty()) {
+            dataItem.setTag(null);
+        }
+
         return dataItem;
     }