Fix use-storybook-testing-library default export handling

[shilman]

Issue: #15

What Changed

Fixed handling of

import userEvent from '@testing-library/user-event';
import userEvent, { foo, bar as Bar } from '@testing-library/user-event';

Checklist

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• Tests are updated
• Documentation is updated

Change Type

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• documentation
• patch
• minor
• major

[yannbf]

Awesome stuff @shilman !! Tested locally and it works perfectly 👌

[github-actions]

🚀 PR was released in v0.3.0 🚀