refactor: add internal types for public assets

[danielroe]

🔗 Linked issue

❓ Type of change

• 📖 Documentation (updates to the documentation or readme)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

We had an untyped asset which can safely produce types for. This PR improves internal type safety but no bug or issue was encountered with the code.

📝 Checklist

• I have linked an issue or discussion.
• I have updated the documentation accordingly.

[codecov]

Codecov Report

Merging #1460 (070afad) into main (e87e2ba) will decrease coverage by 0.03%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #1460      +/-   ##
==========================================
- Coverage   76.17%   76.14%   -0.03%     
==========================================
  Files          73       73              
  Lines        7437     7428       -9     
  Branches      728      728              
==========================================
- Hits         5665     5656       -9     
  Misses       1771     1771              
  Partials        1        1              

Impacted Files	Coverage Δ
src/rollup/plugins/public-assets.ts	92.68% <100.00%> (-0.50%)	⬇️

[pi0]

Thanks 💯