fix(beta): revert to styled-components v5, export it after fixes

[dziraf]

BREAKING CHANGE: styled-components are now re-exported by @adminjs/design-system/styled-components to fix this library's issues with ESM

[github-actions[bot]]

:tada: This PR is included in version 4.0.0-beta-v4.8 :tada:

The release is available on:

• npm package (@beta-v4 dist-tag)
• GitHub release

Your semantic-release bot :package::rocket: