Update freshness

Confirmed article freshness at the time I updated this article, but forgot to update ms.date so doing that now.

Author: austinmccollum

articles/sentinel/billing.md

@@ -6,7 +6,7 @@ author: austinmccollum
 ms.author: austinmc
 ms.custom: subject-cost-optimization
 ms.topic: concept-article
-ms.date: 04/25/2024
+ms.date: 03/31/2025
 ms.collection: usx-security
 appliesto:
     - Microsoft Sentinel in the Microsoft Defender portal