Improve OnCreatingTicket test

Rather than turn off an Apple-specific option, just freeze the JWT security token handler to always treat a token as valid instead.

Author: martincostello

test/AspNet.Security.OAuth.Providers.Tests/OAuthTests`1.cs

@@ -142,18 +142,14 @@ public async Task OnCreatingTicket_Is_Raised_By_Handler()
 
             void ConfigureServices(IServiceCollection services)
             {
+                services.AddSingleton<System.IdentityModel.Tokens.Jwt.JwtSecurityTokenHandler, FrozenJwtSecurityTokenHandler>();
                 services.PostConfigureAll<TOptions>((options) =>
                 {
                     options.Events.OnCreatingTicket = (context) =>
                     {
                         onCreatingTicketEventRaised = true;
                         return Task.CompletedTask;
                     };
-
-                    if (options is Apple.AppleAuthenticationOptions appleOptions)
-                    {
-                        appleOptions.ValidateTokens = false; // Apple test token has expired
-                    }
                 });
             }