Set the enabled_block for tx_bytes_limit to 3938200

Author: platfowner

blockchain-configs/testnet-prod/timer_flags.json

@@ -64,7 +64,7 @@
     "has_bandage": true
   },
   "update_tx_bytes_limit": {
-    "enabled_block": null,
+    "enabled_block": 3938200,
     "has_bandage": true
   }
 }