feat: add duration column to HTTP Client in related entries

[florenmoya]

This PR adds the duration column to the HTTP Client tab in the RelatedEntries component.

Benefit to end users:
Users can now see HTTP client request durations directly in the related entries panel without clicking into each entry individually.

Why it doesn't break existing features:

• Adds a new column only, no removal or modification of existing functionality
• Uses the same entry.content.duration field already available in the data
• Follows the same pattern used in the main /telescope/client-requests index and the Queries tab

Makes building web applications easier:
When debugging slow requests, developers can quickly identify which outgoing HTTP calls are taking the longest without navigating away from the request preview.

Screenshot: