Add using directive for System.Linq

Author: baywet

src/abstractions/RequestInformation.cs

@@ -8,6 +8,7 @@
 using System.ComponentModel;
 using System.Diagnostics;
 using System.IO;
+using System.Linq;
 using System.Reflection;
 using System.Runtime.Serialization;
 using Microsoft.Kiota.Abstractions.Extensions;