fixed ms.custom error

Author: Michael Bender

articles/virtual-network/quick-create-portal.md

@@ -6,7 +6,8 @@ author: asudbring
 ms.author: allensu
 ms.date: 06/06/2023
 ms.topic: quickstart
-ms.service: virtual-network, ai-video-concept
+ms.service: virtual-network
+ms.custom: ai-video-concept
 #Customer intent: I want to use the Azure portal to create a virtual network so that virtual machines can communicate privately with each other and with the internet.
 ---