Allowing AuthorizeForScopesAttribute to specify an alternate AuthenticationScheme name (#868)

Author: DrEsteban

src/Microsoft.Identity.Web/AuthorizeForScopesAttribute.cs

@@ -43,6 +43,11 @@ public class AuthorizeForScopesAttribute : ExceptionFilterAttribute
         /// </summary>
         public string? UserFlow { get; set; }
 
+        /// <summary>
+        /// Allows specifying an AuthenticationScheme if OpenIdConnect is not the default challenge scheme.
+        /// </summary>
+        public string? AuthenticationScheme { get; set; }
+
         /// <summary>
         /// Handles the <see cref="MsalUiRequiredException"/>.
         /// </summary>
@@ -115,7 +120,14 @@ public override void OnException(ExceptionContext context)
                         }
                     }
 
-                    context.Result = new ChallengeResult(properties);
+                    if (AuthenticationScheme != null)
+                    {
+                        context.Result = new ChallengeResult(AuthenticationScheme, properties);
+                    }
+                    else
+                    {
+                        context.Result = new ChallengeResult(properties);
+                    }
                 }
             }