#7287434 Onboarding step for showcasing verticalized designs

Changes proposed in this Pull Request

This PR adds an onboarding step where sites with vertical data will be shown verticalized designs instead of non-verticalized ones. In order to keep the scope small, this PR will focus on the onboarding flow and screen layout.

What to test

• Verticalized design picker is implemented as shown in 42PgVsdlQ1v2wpk6lmmrnq-fi-1697%3A54130 for both desktop and mobile resolutions.
• Traditional design picker works as before, and not broken because of the changes in this PR.

What not to test

• Thumbnail/preview content.
• Interactions such as clicking on thumbnails, “View more options” button, or “Continue” button.
• Improvements to the traditional design picker.
• Good-to-have layout optimizations:
  • Dynamic thumbnail height
  • Onboarding progress bar
  • “Continue” button to be always visible.

Testing instructions

• Head to the onboarding screen /setup/intent?siteSlug=${site_slug}
• Click on the “Start building” button, and expect to land on the verticalized design picker.
• Check that the screen is as per spec.
• Change resolution to mobile ( < 600px).
• Check that the screen is as per spec.
• Click on the “Back” button, back to the onboarding screen.
• Click on the “Start writing” button, click the “Continue” button, and expect to land on the traditional design picker.
• Expect that the traditional design picker looks and works as before.

Desktop:

Mobile:

Related to #62237