Remove unused using directives flagged by Copilot reviewer

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: 2 people

tests/Microsoft.Identity.Test.Unit/CoreTests/WsTrustTests/WsTrustResponseExtendedTests.cs

@@ -2,9 +2,7 @@
 // Licensed under the MIT License.
 
 
-using System;
 using System.Xml.Linq;
-using Microsoft.Identity.Client.Internal;
 using Microsoft.Identity.Client.WsTrust;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 

tests/Microsoft.Identity.Test.Unit/UtilTests/Base64UrlHelpersExtendedTests.cs

@@ -3,7 +3,6 @@
 
 
 using System;
-using System.Text;
 using Microsoft.Identity.Client.Utils;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 

tests/Microsoft.Identity.Test.Unit/WebUITests/AuthorizationResultExtendedTests.cs

@@ -3,11 +3,8 @@
 
 
 using System;
-using System.Collections.Generic;
 using Microsoft.Identity.Client;
-using Microsoft.Identity.Client.OAuth2;
 using Microsoft.Identity.Client.UI;
-using Microsoft.Identity.Client.Utils;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 
 namespace Microsoft.Identity.Test.Unit.WebUITests