Allow returning more fields of the `IotaTransactionBlockResponse`

[wulfraem]

Currently, when sponsoring transactions, we can already switch the behavior to wait for local execution, but we only get the effects part of the transaction response.

It would be nice to get more fields of the transaction response (in my case, I was missing the objectChanges, which is useful to check for created objects, as this one also contains type information), preferable being able to select which fields I want to be returned.

Similar to the request_type field, we could add an optional field, that maps to the options argument in the iota_client.quorum_driver_api().execute_transaction_block(...) call.

Also, check, if we can ignore empty result fields. E.g. a response for a rejected transaction currently looks like this:

{
    "effects": null,
    "error": "Access denied by access controller"
}