Use managed identity instead of AzureWebJobsStorage to connect a function app to a storage account

alexandrenedelec NeilHall-MSFT Currently it's recommended to use identity on dedicated app service plan as it doesn't need WEBSITE_CONTENTAZUREFILECONNECTIONSTRING for file share. Comparing with secret, managed identity allows you to grant access to resources based on roles and permissions, providing greater control and granularity over access to storage resources. Administrator can assign the appropriate roles to different users and service principals to limit permissions and enforce a principle of least privilege. Storage shared key provides more granular control over access to resources, allowing you to define specific permissions related to different operations, such as read, write, or delete operations. The choice of which method to use typically depends on the specific needs, security concerns, and implementation requirements of your application or service.