Fix logout validation logic to handle null HistoryEntryState properly

Co-authored-by: javiercn <[email protected]>

Author: Copilot

src/Components/WebAssembly/WebAssembly.Authentication/src/RemoteAuthenticatorViewCore.cs

@@ -278,7 +278,7 @@ private async Task ProcessLogInCallback()
 
     private async Task ProcessLogOut(string returnUrl)
     {
-        if (Navigation.HistoryEntryState != null && !ValidateSignOutRequestState())
+        if (Navigation.HistoryEntryState == null || !ValidateSignOutRequestState())
         {
             Log.LogoutOperationInitiatedExternally(Logger);
             Navigation.NavigateTo(ApplicationPaths.LogOutFailedPath, AuthenticationNavigationOptions with { HistoryEntryState = "The logout was not initiated from within the page." });