Add information on user-assigned managed identity to best practices for Azure SDK in ASP.NET Core docs

[adrianhall]

Describe the issue or suggestion

DocLink: https://learn.microsoft.com/en-us/dotnet/azure/sdk/aspnetcore-guidance?tabs=api

Just saw the article on best practices for using Azure SDK in ASP.NET Core - awesome article, btw.

However, I noticed it didn’t discuss the use of user-assigned identities in there, especially in the bit about using and injecting azure.identity credentials. Given that user-assigned identities are recommended by the azure architecture center for enterprise applications, it would be a good idea to have a section on how to inject a token credential based on a user-assigned managed identity (instead of the defaultazurecredential, which doesn’t handle user-assigned managed identities without further configuration).

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Document Details

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• ID: 0678c26-dfe9-2c34-faa0-61e9e36b946c
• Version Independent ID: b12bbaa8-941b-2cc8-da41-2cca3d609027
• Content: Best practices for using the Azure SDK with ASP.NET Core - .NET
• Content Source: docs/azure/sdk/aspnetcore-guidance.md
• Service: dotnet-azure
• GitHub Login: @alexwolfmsft
• Microsoft Alias: alexwolf