Fix missing github_utils.py download in PR CI dashboard workflow (#47668)
The update_pr_ci_dashboard_recap.py script imports from github_utils,
but the workflow only downloaded the main script. Now both files are
fetched from the same SCRIPT_REF (main branch SHA) for consistency.
Co-authored-by: ydshieh <ydshieh@users.noreply.github.com>