#7918157 BBE Landing: Update EN showcase images

Related to pdh1Xd-1DL-p2#comment-2228

Proposed Changes

• Updates the images of the site build showcase on the BBE landing page.
• Also updates the document title to Let us build your site.

Testing Instructions

• Go to /setup/site-setup/difmStartingPoint?siteSlug=.
• Confirm that the new images are displayed in the slide show.
• Confirm that the document title has been updated.

Pre-merge Checklist

• Has the general commit checklist been followed? (PCYsg-hS-p2)
• Have you written new tests for your changes?
• Have you tested the feature in Simple (P9HQHe-k8-p2), Atomic (P9HQHe-jW-p2), and self-hosted Jetpack sites (PCYsg-g6b-p2)?
• Have you checked for TypeScript, React or other console errors?
• Have you used memoizing on expensive computations? More info in Memoizing with create-selector and Using memoizing selectors and Our Approach to Data
• Have we added the “[Status] String Freeze” label as soon as any new strings were ready for translation (p4TIVU-5Jq-p2)?
• For changes affecting Jetpack: Have we added the “[Status] Needs Privacy Updates” label if this pull request changes what data or activity we track or use (p4TIVU-ajp-p2)?