Update network configuration requirements for Maia

Added `mxassist.rnd.mendix.com` to the subdomain list

Author: Yiyun333

content/en/docs/refguide/modeling/mendix-ai-assistance/_index.md

@@ -29,7 +29,7 @@ For more information on how to ensure optimal performance of Maia, see the [Best
 
 To ensure the smooth operation of Mendix AI Assistance (Maia), the following network requirements must be met:
 
-* Ensure access to hostnames within the `maia.mendix.com` subdomain
+* Ensure access to hostnames within the `maia.mendix.com` and `mxassist.rnd.mendix.com` subdomains
 * Allow secure network traffic through port 443 (HTTPS) to enable uninterrupted operation of Maia
 
 ## Maia Capabilities in Mendix Studio Pro