fix: #3625697 Print the blog cards of the listing as second level headings

Rajab Natshahrequested to merge
issue/website_starter-3625697:3625697-card-heading-level into 1.0.x

The blog listing prints its own h1, so the teaser cards skipped a heading level.

Issue: https://www.drupal.org/node/3625697

AI-Generated: Yes

Merge request reports