Add Warning about failures due to minAPIVersion

A common cause for customer's opening support cases is if they set minAPIVersion property of API Management to a very recent version, newer than what we tell az mon to use to connect to us when creating a diagnostic settings object. This results in a failure and the error message is not very descriptive. Az Mon team has indicated they can't change the error message reported back to users, hence the doc update is being submitted.

Author: tehnoonr

articles/api-management/api-management-howto-use-azure-monitor.md

@@ -138,6 +138,8 @@ To configure resource logs:
 
 For more information, see [Create diagnostic settings to send platform logs and metrics to different destinations](../azure-monitor/essentials/diagnostic-settings.md).
 
+> [!NOTE]
+> Adding diagnostic setting object may result in a failure if the [MinApiVersion property](https://learn.microsoft.com/en-us/dotnet/api/microsoft.azure.management.apimanagement.models.apiversionconstraint.minapiversion) of your API Management service is set to any API Version higher than 2019-12-01. 
 ## View diagnostic data in Azure Monitor
 
 If you enable collection of GatewayLogs or metrics in a Log Analytics workspace, it can take a few minutes for data to appear in Azure Monitor. To view the data:
@@ -211,4 +213,4 @@ In this tutorial, you learned how to:
 Advance to the next tutorial:
 
 > [!div class="nextstepaction"]
-> [Trace calls](api-management-howto-api-inspector.md)
+> [Trace calls](api-management-howto-api-inspector.md)