Not terminated hunt status

**Environment**
- How did you install GRR? Docker image
- What GRR version are you running?: 3.4.0.1
- What operating system does the GRR server run on? Linux
- What operating system does the affected GRR client run on, if applicable? Windows 10

**Describe the issue**
It is possible to know that a flow has finished when its status changes to `TERMINATED`. However, regarding hunts, the status is always `STARTED` even if all clients are completed or the expiry time has passed. I would like to know when a hunt has finished to know when I can start downloading artifacts of all the clients involved. I don't know if there's a reason why it is made this way or if this is an error.

Thanks in advance