Fix prisoners for examples dashboard

[thpani]

Fix prisoners example in the dashboard.

This one only needed a --main flag, and fixing the import statement (which is to be revised).

[konnov]

LGTM

[bugarela]

We shouldn't need the export at all once some stuff I'm working on gets to main 😄 I actually have this same change in my local diff.

[bugarela]

I see there are failing integration tests. That's because the run command still requires the export. I have a fix for that locally, I'll see if I can easily extract it from my changes into a PR. If you can hold this until then, that'd be great.