fix(CheckboxInput & RadioInput): add className to wrapper

[kimanhou]

Done

• Add a classname to CheckboxInput and RadioInput to easily target them in CSS.
• In preparation of a fix in vanilla framework: fix(CheckboxInput & RadioInput): handle wrapper vanilla-framework#5818

QA

Pinging @canonical/react-library-maintainers for a review.

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• Steps for QA.

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Fixes

Fixes: # .

[github-actions]

🎉 This PR is included in version 4.6.2 🎉

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