Update AttachRedirectUri to use ValidateAuthorizationRequestContext.IsRejected

src/OpenIddict.Server/OpenIddictServerHandlers.Authentication.cs

@@ -1629,7 +1629,7 @@ namespace OpenIddict.Server
 
                     // Note: at this stage, the validated redirect URI property may be null (e.g if an error
                     // is returned from the ExtractAuthorizationRequest/ValidateAuthorizationRequest events).
-                    if (!string.IsNullOrEmpty(notification?.RedirectUri))
+                    if (notification != null && !notification.IsRejected)
                     {
                         context.RedirectUri = notification.RedirectUri;
                     }

src/OpenIddict.Server/OpenIddictServerHandlers.Session.cs

@@ -528,7 +528,7 @@ namespace OpenIddict.Server
 
                     // Note: at this stage, the validated redirect URI property may be null (e.g if
                     // an error is returned from the ExtractLogoutRequest/ValidateLogoutRequest events).
-                    if (!string.IsNullOrEmpty(notification?.PostLogoutRedirectUri))
+                    if (notification != null && !notification.IsRejected)
                     {
                         context.PostLogoutRedirectUri = notification.PostLogoutRedirectUri;
                     }