Remove sx rom the Select component

[liuliu-dev]

Closes #5833

• sx usage
  tracking here: https://github.com/github/primer/issues/5827

Changelog

Removed

Removed sx from Select.

Rollout strategy

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

[changeset-bot]

🦋 Changeset detected

Latest commit: 0cb9504

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

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[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	87.92 KB (-0.07% 🔽)
packages/react/dist/browser.umd.js	88.07 KB (-0.01% 🔽)

[primer-integration]

👋 Hi from github/github-ui! Your integration PR is ready: https://github.com/github/github-ui/pull/1978

[primer-integration]

🟢 ci completed with status success.

[Copilot]

Pull Request Overview

This PR removes the sx prop from the Select component as part of a breaking change in a major version release. The change eliminates styled-components API support in favor of CSS Modules approach.

• Remove sx prop from SelectProps type definition and component implementation
• Update Storybook configuration to exclude the removed prop from controls
• Add changeset documentation for the breaking change

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
packages/react/src/Select/Select.tsx	Removes sx prop from destructuring and TextInputWrapper component usage
packages/react/src/Select/Select.stories.tsx	Updates Storybook controls exclude list to remove sx
.changeset/new-shrimps-appear.md	Documents the breaking change for release notes