Docs: add href to active pagination sizing links

[Kevinjohn]

Description

Adds missing href="#" attributes to the active links in the pagination sizing examples.

Motivation & Context

The sizing examples use active <a> elements with aria-current="page", but those anchors lacked href attributes. The page's canonical active example already uses href="#" for the same pattern.

Expected: the active pagination links in sizing examples follow the documented active-link pattern.
Actual: the active pagination links are anchors without href attributes.

This updates the large and small pagination examples to match the active example on the same page.

Type of changes

• 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

• I have read the contributing guidelines
• 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-42709--twbs-bootstrap.netlify.app/

Related issues

None.

Checks

• git diff --check
• npm exec -- prettier --config site/.prettierrc.json -c site/src/content/docs/components/pagination.mdx
• npm run docs-build