Update user-agents.mdx (#17390)

Author: DRayCloudflare

src/content/partials/speed/user-agents.mdx

@@ -11,7 +11,9 @@ Cloudflare Observatory tests are generated with the following user agents:
 * Mozilla/5.0 (Linux; Android 11; Moto G Power (2022)) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/109.0.0.0 Mobile Safari/537.36
 * Mozilla/5.0 (Macintosh; Intel Mac OS X 10\_15\_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/109.0.0.0 Safari/537.36
 
-Cloudflare Observatory tests originate from ASN 15169.
+Cloudflare Observatory tests originate from: 
+* IPv6: ASN 15169.
+* IPv4: ASN 396982.
 
 
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