Update web-analytics/faq.mdx

[MildMax]

Summary

• Adds documentation to Web Analytics FAQs describing the circumstances under which the */cdn-cgi/rum endpoint would return a 405 status code

Screenshots (optional)

Documentation checklist

• Is there a changelog entry (guidelines)? If you don't add one for something awesome and new (however small) — how will our customers find out? Changelogs are automatically posted to RSS feeds, the Discord, and X.
• The change adheres to the documentation style guide.
• If a larger change - such as adding a new page- an issue has been opened in relation to any incorrect or out of date information that this PR fixes.
• Files which have changed name or location have been allocated redirects.

[github-actions]

This pull request requires reviews from CODEOWNERS as it changes files that match the following patterns:

Pattern	Owners
/src/content/changelog/	@cloudflare/pm-changelogs, @cloudflare/product-owners
/src/content/docs/web-analytics/	@angelampcosta, @dcpena, @cloudflare/product-owners

[github-actions]

Preview URL: https://4a2098f6.preview.developers.cloudflare.com
Preview Branch URL: https://jburns-rum-405-faq.preview.developers.cloudflare.com

Files with changes (up to 15)

Original Link	Updated Link
https://developers.cloudflare.com/changelog/post/2026-05-13-rum-405-method-not-allowed/	https://jburns-rum-405-faq.preview.developers.cloudflare.com/changelog/post/2026-05-13-rum-405-method-not-allowed/
https://developers.cloudflare.com/web-analytics/faq/	https://jburns-rum-405-faq.preview.developers.cloudflare.com/web-analytics/faq/