feat: nested checkbox

[Tresau]

Closes #12434

creates a new component called <NestedCheckbox/> that allows the user to control a group of checkbox from a single parent checkbox

Changelog

New

• the NestedCheckbox component

Changed

• Checkbox story documentation

Removed

• N/A

Testing / Reviewing

ensure that the unit tests run properly. Ensure that the Nested section of the checkbox on the stories runs correctly. Ensure the overview runs and the documentation for NestedCheckbox is there and accurate.

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[Tresau]

Currently working on a bug where parent nested checkboxes do not always reflect the correct state of child nested checkboxes.

this is happening because changing from checked or unchecked to indeterminate does not fire an onChange event, I have a couple ideas on how to address this and will test them out.