feat(upload): add resetUpload method to clear uploaded files

[onaranyusuf]

🔗 Linked issue

N/A

❓ Type of change

• [ ] 📖 Documentation (updates to the documentation, readme or JSdoc annotations)
• [ ] 🐞 Bug fix (a non-breaking change that fixes an issue)
• [ ] 👌 Enhancement (improving an existing functionality like performance)
• [x] ✨ New feature (a non-breaking change that adds functionality)
• [ ] 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• [ ] ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

Do we need to publish a new version of a package?

• [x] Add a changeset pnpm changeset and select what semver changes your PR is adding
  • commit and push the generated changeset file

📝 Checklist

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

📚 Description

This PR adds a new method resetUpload() to the component.

It allows:

• Manually clearing selected file(s)
• Resetting validation state (e.g., after successful form submission)
• Resetting native input value to allow re-upload of the same file

Currently, there is no built-in way to programmatically reset the upload input. This makes it difficult to clear the component after successful form submissions or cancellation actions. This method provides a clean, predictable way to reset the UI and internal state.

Tested successfully in a Nuxt 3 app using both direct usage and custom wrapper components.