Previous and Next buttons are missing arrows on the site picker

[markbiek]

Steps to reproduce:

1. Go to https://wordpress.com/setup/hosted-site-migration/sitePicker
2. Scroll to the bottom of the page.
3. The Previous and Next buttons are missing arrows.

[github-actions]

OpenAI suggested the following labels for this issue:

• [Feature Group] Accessibility & Navigation: The issue relates to the navigation experience, specifically the missing visual indicators (arrows) on navigation buttons.
• [Feature] Site Navigation: This feature directly involves how users navigate through the site, affecting the usability of the previous and next buttons.
• [Feature] Context Menu: The context provided suggests that there may be interaction elements involved that need clearer navigation.