Duplicate association charges same fee as successful association

### Description

Associating an account to the same token twice results in identical transaction fees for both the successful and unsuccessful transaction.

### Steps to reproduce

Created two accounts on testnet and created a fungible token with the first.
With the second account, I associated with the new token once (successful)
I then associated the same (second) account to the same token (failed with duplicate)

This is as expected, **however the fee charged for both the successful and failed transaction was the same**, I would have expected the second to be cheaper since no state change occurred.

Successful transaction
https://testnet.dragonglass.me/transactions/00265609461641819850122147892

Failed transaction
https://testnet.dragonglass.me/transactions/00265609461641819848360907851

### Additional context

_No response_

### Hedera network

testnet

### Version

v0.21

### Operating system

_No response_

Start by comparing the successful and failed association transactions linked in the issue, then trace the transaction-fee handling in the Java repository. No source file or test is named, so identify the association and duplicate-failure fee paths first. Done means a duplicate association is charged less when it makes no state change, with coverage for both transactions.

Written by the indexing model from the issue text.