add sx support back to ProgressBar.tsx

[llastflowers]

Revert breaking changes introduced in #6676 until we can migrate the sx usage with ProgressBar in github-ui to @primer/styled-react. This unblocks integration tests for primer/react changes against github/github-ui

Changelog

New

Changed

Removed

Rollout strategy

• Patch release
• Minor release
• Major release; if selected, include a written rollout or migration plan
• None; if selected, include a brief description as to why—No changeset needed, as this PR only reverts changes on main that have not yet been released

Testing & Reviewing

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]

⚠️ No Changeset found

Latest commit: 407f5a7

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes changesets to release 2 packages

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

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[github-actions]

size-limit report 📦

Path	Size
packages/react/dist/browser.esm.js	87.94 KB (0%)
packages/react/dist/browser.umd.js	88.16 KB (0%)

[primer-integration]

👋 Hi from github/github-ui! Your integration PR is ready: https://github.com/github/github-ui/pull/1907

[primer-integration]

🟢 ci completed with status success.

[Copilot]

Pull Request Overview

This PR reverts breaking changes to ProgressBar.tsx by re-adding sx prop support that was previously removed. The purpose is to unblock integration tests with github-ui while maintaining backward compatibility until a proper migration can be completed.

• Restores SxProp type import and usage
• Adds sx prop support back to StyledProgressContainerProps and ProgressBarItems types

[github-actions]

👋 Hi, there are new commits since the last successful integration test. We recommend running the integration workflow once more, unless you are sure the new changes do not affect github/github. Thanks!