Remove support for sx from CheckboxGroup component

[llastflowers]

Closes https://github.com/github/primer/issues/5760

Current sx usage: 1

❌ Still need to separately update github-ui components to use @primer/styled-react
github/github-ui PR: https://github.com/github/github-ui/pull/1676

Changelog

Removed

Remove support for sx from the CheckboxGroup component, and associated stories, docs, and tests

Rollout strategy

• Major release; if selected, include a written rollout or migration plan

We are using the @primer/styled-react component to mitigate removing sx usage. We will make sure usage is updated upstream before merging.

Merge checklist

• Added/updated tests
• Added/updated documentation
• Added/updated previews (Storybook)
• Changes are SSR compatible
• Tested in Chrome
• Tested in Firefox
• Tested in Safari
• Tested in Edge
• (GitHub staff only) Integration tests pass at github/github (Learn more about how to run integration tests)

[changeset-bot]

🦋 Changeset detected

Latest commit: 4eb192a

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@primer/react	Major
@primer/styled-react	Major

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[github-actions]

👋 Hi, this pull request contains changes to the source code that github/github depends on. If you are GitHub staff, we recommend testing these changes with github/github using the integration workflow. Thanks!

[github-actions]

size-limit report 📦

Path	Size
packages/react/dist/browser.esm.js	89.52 KB (0%)
packages/react/dist/browser.umd.js	89.62 KB (0%)

[Copilot]

Pull Request Overview

This PR removes the sx prop support from the CheckboxGroup component as part of a design system migration strategy. The change eliminates the ability to pass custom styling through the sx prop, with teams expected to use @primer/styled-react as an alternative for custom styling needs.

Key changes:

• Removal of SxProp type from CheckboxGroup component interface
• Documentation updates removing sx prop references from all subcomponents
• Test story cleanup removing sx-related test cases

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

File	Description
packages/react/src/CheckboxGroup/CheckboxGroup.tsx	Removes SxProp import and type union, eliminating sx prop support from the main component
packages/react/src/CheckboxGroup/CheckboxGroup.docs.json	Updates component documentation by removing deprecated sx prop entries from main component and all subcomponents
e2e/components/CheckboxGroup.test.ts	Removes visual regression test for sx props functionality
.changeset/tame-ducks-ring.md	Adds major version changeset documenting the breaking change

[primer-integration]

👋 Hi from github/github-ui! Your integration PR is ready: https://github.com/github/github-ui/pull/2772

[primer-integration]

🟢 ci completed with status success.