[CI] Only report registry format errors by default

[chalin]

• Followup to Introduce schema for registry entries #4805
• When running check:registery locally, only display warnings and notices when the --debug flag is provided. To do so run the script like this:
  npm run check:registry -- --debug

/cc @svrnm

[chalin]

Thanks for the review @tiffany76 ✨
@svrnm - going to merge now. We can always readjust if you'd prefer another solution.