Removes IdentityServer4 usage

Extensions/Extensions.cs

@@ -1,20 +1,10 @@
 using System;
-using IdentityServer4.Models;
 using Microsoft.AspNetCore.Mvc;
 
 namespace nuget_host.Models
 {
     public static class Extensions
     {
-        /// <summary>
-        /// Checks if the redirect URI is for a native client.
-        /// </summary>
-        /// <returns></returns>
-        public static bool IsNativeClient(this AuthorizationRequest context)
-        {
-            return !context.RedirectUri.StartsWith("https", StringComparison.Ordinal)
-               && !context.RedirectUri.StartsWith("http", StringComparison.Ordinal);
-        }
 
         public static IActionResult LoadingPage(this Controller controller, string viewName, string redirectUri)
         {