Add the test module for storybook tests

## Feature Description

Add a test module exclusively for storybook to test the components like `ReportErrorWrapper` so that we do not need to pass a real module to such components. Refer to the [comment](https://github.com/google/site-kit-wp/pull/11221#discussion_r2248940154) on #11221

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## Acceptance criteria

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## Implementation Brief

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### Test Coverage

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## QA Brief

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## Changelog entry

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Start by reviewing the ReportErrorWrapper component and the discussion on pull request #11221 that motivates this request. The work is done when Storybook has a dedicated test module that can test such components without passing a real module.

Written by the indexing model from the issue text.