Transaction failure reason not visible when using fixed gas amount

FireFly normally reports custom error messages all the way back to the API response which is really helpful for developers. Typically, if a transaction will fail, it will also fail the gas estimation step which happens synchronously with submitting the transaction, so the custom error message is reported immediately.

If I submit a transaction, by invoking a custom contract API and adding a fixed gas amount, the behavior is different.
```json
{
"input": {},
"options": {
"gas": "20000"
}
}
```

The request is accepted with a `202` and internally gas estimation is skipped (I think). This results in a failed transaction, but my custom error message does not show up in the Operation Output or Details so it is really hard to know why the transaction failed, especially if I have complex logic that could reject the transaction for one of several reasons.