Update api.php
Update api.php

to avoid getting error:
```
Unable to prepare route [api/v1/insight/transfer/asset] for serialization. Another route has already been assigned name [api.v1.insight.income.asset].
```
JC5/firefly-iii,firefly-iii/firefly-iii,firefly-iii/firefly-iii,firefly-iii/firefly-iii,JC5/firefly-iii,firefly-iii/firefly-iii