RPC simulateBundle response is not fully camelCase

[futurekarol]

in case of a failed bundle simulation the tx_signature field in the json response is in snake_case and not camelCase like all the other fields.

example response:

{
      "context": {
        "apiVersion": "1.13.7",
        "slot": 183287630
      },
      "value": {
        "summary": {
          "failed": {
            "error": {
              "TransactionFailure": {
                "InstructionError": [
                  2,
                  {
                    "Custom": 6001
                  }
                ]
              }
            },
            "tx_signature": "3RQxXBZ3V2vmAW8Nq17neRvBwB4DABp5bDCL156aom6bciUa4cGDSVZvHNPYGL3cMuJStv4VYwxKuMHWkEyJ394U"
          }
        },
        "transactionResults": [
          {
            "err": {
              "InstructionError": [
                2,
                {
                  "Custom": 6001
                }
              ]
            },
            "logs": [
              "Program ComputeBudget111111111111111111111111111111 invoke [1]",
              "Program ComputeBudget111111111111111111111111111111 success",
              "Program ComputeBudget111111111111111111111111111111 invoke [1]",
              "Program ComputeBudget111111111111111111111111111111 success",
            ],
            "postExecutionAccounts": null,
            "preExecutionAccounts": null,
            "unitsConsumed": 199577
          }
        ]
      }
    }
    ```