Studio: Ensure that images render correctly with the new library

[katinthehatsite]

Related issues

Related to STU-1668

How AI was used in this PR

The change was straightforward, it was not needed

Proposed Changes

This PR ensures that we whitelist https://blueprintslibraryv2.wpcomstaging.com/ where the new blueprints library is located: https://blueprintslibraryv2.wpcomstaging.com/
This will ensure that the images are rendered correctly for the blueprints that we use from that library.

Testing Instructions

• Apply the diff from 214152-ghe-Automattic/wpcom
• Sandbox the public API
• Pull the changes from this branch
• Start Studio
• Enable the Enable Blueprints Gallery feature flag
• Click on Add site > Build a new site
• Confirm that thumbnails for blueprints are rendering correctly

Pre-merge Checklist

• Have you checked for TypeScript, React or other console errors?

[wpmobilebot]

📊 Performance Test Results

Comparing 72ea756 vs trunk

app-size

Metric	trunk	72ea756	Diff	Change
App Size (Mac)	1404.88 MB	1404.88 MB	+0.00 MB	⚪ 0.0%

site-editor

Metric	trunk	72ea756	Diff	Change
load	1528 ms	1517 ms	11 ms	⚪ 0.0%

site-startup

Metric	trunk	72ea756	Diff	Change
siteCreation	8093 ms	8085 ms	8 ms	⚪ 0.0%
siteStartup	4941 ms	4931 ms	10 ms	⚪ 0.0%

---

Results are median values from multiple test runs.

Legend: 🟢 Improvement (faster) | 🔴 Regression (slower) | ⚪ No change (<50ms diff)