Revert "Remove support for sx from BaseStyles component"

[jonrohan]

Reverts #6878

[changeset-bot]

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Latest commit: 8999c87

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[Copilot]

Pull Request Overview

This PR reverts the removal of sx prop support from the BaseStyles component, restoring its ability to accept system props and sx styling. This is a breaking change reversion that brings back previously removed functionality.

• Restores sx prop support to BaseStyles component type definitions
• Re-implements BoxWithFallback wrapper to enable system props handling
• Adds comprehensive test coverage for the restored functionality

Reviewed Changes

Copilot reviewed 5 out of 23 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
packages/react/src/BaseStyles.tsx	Restores SxProp type and BoxWithFallback wrapper implementation
packages/react/src/tests/BaseStyles.test.tsx	Adds unit test for system props functionality
packages/react/src/BaseStyles.dev.stories.tsx	Adds Storybook examples demonstrating sx and system props usage
e2e/components/BaseStyles.test.ts	Updates e2e test configuration to include new story variants
.changeset/sharp-beans-run.md	Removes the changeset entry for the original breaking change

[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!

[primer-integration]

👋 Hi from github/github-ui! Your integration PR is ready: https://github.com/github/github-ui/pull/3651

[primer-integration]

🔴 ci completed with status failure.