Update agent and flow list item component

What does this MR do and why?

This MR's changes align the AI Catalog's agent and flow list items' shared design to the most recent design.

TODOS

• Confirm changes with team
• Ensure responsiveness
• Update tests

References

Screenshots or screen recordings

Before	After

How to set up and validate locally

1. Make sure the :global_ai_catalog feature flag is enabled
2. Navigate to http://gdk.test:3000/explore/ai-catalog/agents/ and http://gdk.test:3000/gitlab-duo/test/-/automate/agents

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Related to #573263