`/account/coins` ignores currencies parameter

[linconvidal]

The /account/coins endpoint does not filter UTXOs by the currencies parameter as specified in the Rosetta spec.

Expected Behavior:
When currencies parameter is provided, should return only UTXOs containing the specified currencies.

Actual Behavior:
Returns all UTXOs regardless of currencies parameter.

Reproduce:

curl -X POST http://localhost:8082/account/coins \
  -H "Content-Type: application/json" \
  -d '{
    "network_identifier": {"blockchain": "cardano", "network": "preprod"},
    "account_identifier": {"address": "addr_test1qrtdh7587yz5m2w504sjhqnrfml5fpcuxu24fj8xwvk48artcrahhulmvvsnmwqk2k3nmrz20sw8uj7htlpnlutk0p9sjfnd3n"},
    "currencies": [{"symbol": "ADA", "decimals": 6}]
  }'

Expected: Returns subset of UTXOs (only ADA-only UTXOs, excluding multi-asset UTXOs)
Actual: Returns all 236 UTXOs including those with native assets

Spec Reference:

• Mesh docs: https://docs.cdp.coinbase.com/api-reference/mesh/account/get-an-account-unspent-coins.

Note: /account/balance currencies filter works correctly on rosetta-java v1.3.3.