fix(IDX): run repro-check on ic-build image

[cgundy]

This fixes the issue with the repro-check script by introducing a couple changes:

• Run directly inside build-ic image. This is far simpler than setting up podman and starting a new container from inside the CI job
• only output colors if stdout is a terminal (this wasn't working because build-ic.sh is called from a python script for repro-check)

CI job errored out: https://github.com/dfinity/ic/actions/runs/21168798293/job/60880111425

[github-actions]

Run URL: https://github.com/dfinity/ic/actions/runs/21167856913

New container image: sha256:b5163526d698b2ec8b66aba3fb48dbbf40b6825324123edba2d5c170d906fb5b
New container tag: 1025ea65ea5ff7efb433a70c3066d70e1435d5374320e42c221bb78deb24b6d1