Replace DefaultAzureCredential with ManagedIdentityCredential

Author: Priyanka-Microsoft

App/backend-api/Microsoft.GS.DPS.Host/Helpers/azure_credential_utils.cs

@@ -9,6 +9,15 @@ public static class AzureCredentialHelper
     {
         public static TokenCredential GetAzureCredential(string clientId = null)
         {
+            """
+                Returns an Azure credential based on the application environment.
+                If the environment is 'dev', it uses DefaultAzureCredential.
+                Otherwise, it uses ManagedIdentityCredential.
+                Args:
+                    client_id (str, optional): The client ID for the Managed Identity Credential.
+                Returns:
+                    Credential object: Either DefaultAzureCredential or ManagedIdentityCredential.
+            """
             var env = Environment.GetEnvironmentVariable("ASPNETCORE_ENVIRONMENT") ?? "Production";
 
             if (string.Equals(env, "Development", StringComparison.OrdinalIgnoreCase))