refactor: [M3-7544, M3-7552] - ErrorState and FileUploader v7 stories

[coliu-akamai]

Description 📝

• Migrate ErrorState component story to a V7 (.tsx) story
• Migrate FileUploader component story to a V7 (.tsx) story
• Rearrange FileUploader/ObjectUploader files
• Add tests

How to test 🧪

Verification steps

• yarn test ErrorState.test.tsx
• yarn test FileUploader.test.tsx
• yarn test ObjectUploader.test.tsx
• http://localhost:6006/?path=/docs/components-file-uploaders-file-uploader--documentation
• http://localhost:6006/?path=/docs/components-file-uploaders-object-uploader--documentation
• http://localhost:6006/?path=/docs/components-error-state--documentation

As an Author I have considered 🤔

Check all that apply

• 👀 Doing a self review
• ❔ Our contribution guidelines
• 🤏 Splitting feature into small PRs
• ➕ Adding a changeset
• 🧪 Providing/Improving test coverage
• 🔐 Removing all sensitive information from the code and PR description
• 🚩 Using a feature flag to protect the release
• 👣 Providing comprehensive reproduction steps
• 📑 Providing or updating our documentation
• 🕛 Scheduling a pair reviewing session
• 📱 Providing mobile support
• ♿ Providing accessibility support

[coliu-akamai]

closing - branched off incorrect branch