Remove ms.service = application-gateway. Replaced by ms.service = azure-application-gateway

Author: Docs Allowlist Management

articles/application-gateway/v1-retirement.md

@@ -4,7 +4,7 @@ titleSuffix: Azure Application Gateway
 description: This article provides a high-level overview of the retirement of Application gateway V1 SKUs. 
 services: application-gateway
 author: MJyot
-ms.service: application-gateway
+ms.service: azure-application-gateway
 ms.topic: how-to
 ms.date: 04/19/2023
 ms.author: mjyothish