Reenable ability to deploy with private networking (#774)

Author: BMurri

src/deploy-tes-on-azure/Deployer.cs

@@ -494,6 +494,11 @@ await Execute("Validating existing Azure resources...", async () =>
 
                     ConsoleEx.WriteLine($"Deploying TES on Azure version {targetVersion}...");
 
+                    if (!string.IsNullOrEmpty(configuration.BatchNodesSubnetId))
+                    {
+                        configuration.BatchSubnetName = new ResourceIdentifier(configuration.BatchNodesSubnetId).Name;
+                    }
+
                     var vnetAndSubnet = await ValidateAndGetExistingVirtualNetworkAsync();
 
                     if (string.IsNullOrWhiteSpace(configuration.ResourceGroupName))
@@ -538,11 +543,6 @@ await Task.WhenAll(
                                 configuration.BatchSubnetName = string.IsNullOrEmpty(configuration.BatchSubnetName) ? configuration.DefaultBatchSubnetName : configuration.BatchSubnetName;
                                 configuration.VmSubnetName = string.IsNullOrEmpty(configuration.VmSubnetName) ? configuration.DefaultVmSubnetName : configuration.VmSubnetName;
                                 vnetAndSubnet = await CreateVnetAndSubnetsAsync();
-
-                                if (string.IsNullOrEmpty(configuration.BatchNodesSubnetId))
-                                {
-                                    configuration.BatchNodesSubnetId = vnetAndSubnet.Value.batchSubnet.Id;
-                                }
                             }
                         }),
                         Task.Run(async () =>
@@ -609,6 +609,11 @@ await Task.WhenAll(
                         })
                     ]);
 
+                    if (string.IsNullOrEmpty(configuration.BatchNodesSubnetId))
+                    {
+                        configuration.BatchNodesSubnetId = vnetAndSubnet.Value.batchSubnet.Id;
+                    }
+
                     var clientId = managedIdentity.Data.ClientId;
                     var settings = ConfigureSettings(clientId?.ToString("D"));