(AzureCXP) fixes MicrosoftDocs/azure-docs#97933

Adds additional details for ID field - that it is not included in the portal exported dashboard definition.

Author: AnuragSingh-MSFT

articles/azure-portal/azure-portal-dashboards-structure.md

@@ -283,6 +283,8 @@ Let’s break down the relevant sections of the JSON.  The top-level properties,
 
 The Azure resource ID, subject to the [naming conventions of Azure resources](/azure/architecture/best-practices/resource-naming). When the portal creates a dashboard, it generally chooses an ID in the form of a guid, but you can use any valid name when you create them programmatically.
 
+When you export a dashboard from the Azure portal, the `id` property is not included. If you import this JSON file to create a new dashboard in the Azure portal, a new ID value will be assigned to each new dashboard.
+
 ### Name
 
 The name is the segment of the resource ID that does not include the subscription, resource type, or resource group information. Essentially, it's the last segment of the resource ID.