Operation type filtering broken in cardano-rosetta-java

### Context & versions
- **Implementation**: cardano-rosetta-java v1.2.9 (regression from cardano-rosetta)
- **Network**: preprod
- **Endpoint**: `/search/transactions`
- **Comparison**: cardano-rosetta v2.5.0 working correctly

### Steps to reproduce
1. Search for transactions by operation type:
```json
{
"network_identifier": {
"blockchain": "cardano",
"network": "preprod"
},
"type": "withdrawal",
"max_block": 3500000,
"limit": 1
}
```
2. Count operations of the requested type in returned transactions
3. Compare with cardano-rosetta using identical filter

### Actual behavior
Operation type filtering is completely ignored in cardano-rosetta-java:
- **cardano-rosetta-java**: When filtering by `"type": "withdrawal"`, returns transactions with 0 withdrawal operations
- **cardano-rosetta**: Correctly returns transactions containing 1+ withdrawal operations

The implementation accepts the type parameter but ignores it entirely, returning unrelated transactions.

### Expected behavior
Should only return transactions containing operations of the specified type. The older cardano-rosetta implementation correctly returns transactions with withdrawal operations when filtered by type "withdrawal".

Start at the /search/transactions implementation and trace how the type parameter is accepted and applied. Reproduce the preprod request with type "withdrawal" and compare results with cardano-rosetta v2.5.0; done means returned transactions contain one or more operations of the requested type.

Written by the indexing model from the issue text.