1257: allow cloudflare insights on all environments in CSP (#1440)

part of issue:
[1257](RaspberryPiFoundation/digital-editor-issues#1257)

Part of the CSP work - notice that we get CSP on the testing and staging
environments for cloudflare insights code

<img width="647" height="72" alt="missing-CSP-for cloudflare-insights"
src="https://github.com/user-attachments/assets/d7de79a4-dc3b-485b-983e-de1b984152c8"
/>

This change will allow that to be loaded and execute

Author: DNR500

src/scratch.html

@@ -9,7 +9,7 @@
         default-src 'self';
         base-uri 'none';
         object-src 'none';
-        script-src 'self' 'unsafe-inline' 'unsafe-eval';
+        script-src 'self' 'unsafe-inline' 'unsafe-eval' https://static.cloudflareinsights.com;
         style-src 'self' 'unsafe-inline';
         worker-src 'self' blob:;
         child-src 'self' blob:;