Prevent .visually-hidden overflowing children to become focusable

[ffoodd]

Description

Prevent .visually-hidden overflow.

Motivation & Context

@keltroth demonstrated that .visually-hidden children become focusable when overflowing, but remains hidden—conducting to a focus loss. Here's a reduced test case on CodePen using Bootstrap.

Type of changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Refactoring (non-breaking change)
• [ ] Breaking change (fix or feature that would change existing functionality)

Checklist

• [x] I have read the contributing guidelines
• [x] My code follows the code style of the project (using npm run lint)
• [ ] My change introduces changes to the documentation
• [ ] I have updated the documentation accordingly
• [ ] I have added tests to cover my changes
• [ ] All new and existing tests passed

Live previews

• https://deploy-preview-41286--twbs-bootstrap.netlify.app/docs/5.3/helpers/visually-hidden/