No longer validate ES_HOME in ValidateArgumentsTask

We validate the presense of `ES_HOME` but no prior installation to
prevent folks from upgrading from a zip distribution.

We only did this validation on the first custom action as later on we
ourselves set ES_HOME during the installation.

Setting the es var is part of the wxs declaration though and does not
happen as part of a custom action.

When we built and tested this against 6.3.2 our automated testing was
all green. Now using the 6.4.0 snapshot build a vanilla install fails.

This PR removes the check inside the custom action.

Still need to investigate what causes this difference

src/InstallerHosts/Elastic.InstallerHosts/Elasticsearch/Tasks/Immediate/ValidateArgumentsTask.cs

@@ -7,7 +7,7 @@ namespace Elastic.InstallerHosts.Elasticsearch.Tasks.Immediate
 {
 	public class ValidateArgumentsTask : ElasticsearchInstallationTaskBase
 	{
-		public ValidateArgumentsTask(string[] args, ISession session) : base(args, session, installationInProgress: false) { }
+		public ValidateArgumentsTask(string[] args, ISession session) : base(args, session) { }
 
 		protected override bool ExecuteTask()
 		{