using typo

Author: LakshanF

test/dotnet.Tests/TelemetryCommandTest.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.IO;
+using System.Collections.Generic;
 using Microsoft.DotNet.Cli.Utils;
 using Microsoft.DotNet.Tools.Test.Utilities;
 using Xunit;