Add a parameter to reduce retrying watiing time

Log:

```
2024/04/26 10:18:01 waiting and retrying... midjourney: image denied: request cancelled due to image filters
```

This waiting and retrying for 10 minutes. Can you add a parameter to reduce this waiting time?

https://github.com/igolaizola/bulkai/blob/main/pkg/ai/ai.go#L327