Do not copy files to build server for a Delete. (#16752)

The `Delete` task should not need to copy any files to the remote server.
Lets try to set this up by implementing the `ShouldCopyToBuildServer` method.

This should help reduce build times if it works.

msbuild/Xamarin.MacDev.Tasks/MsBuildTasks/Delete.cs

@@ -1,7 +1,10 @@
+using System.Collections.Generic;
+using System.Linq;
+using Microsoft.Build.Framework;
 using Xamarin.Messaging.Build.Client;
 
 namespace Microsoft.Build.Tasks {
-	public class Delete : DeleteBase {
+	public class Delete : DeleteBase, ITaskCallback {
 		public override bool Execute ()
 		{
 			var result = base.Execute ();
@@ -25,5 +28,11 @@ namespace Microsoft.Build.Tasks {
 
 			return result;
 		}
+
+		public bool ShouldCopyToBuildServer (ITaskItem item) => false;
+
+		public bool ShouldCreateOutputFile (ITaskItem item) => false;
+
+		public IEnumerable<ITaskItem> GetAdditionalItemsToBeCopied () => Enumerable.Empty<ITaskItem> ();
 	}
 }