Create parent socket folder in Windows upgrade script

[yophilav]

TL;DR - The windows install script creates the mnt folder in the install scenario (Initialize-IoTEdge) but not the upgrade scenario, which is inconsistent and causes problems. This change addresses the missed case.

Context :
Recently we have updated that each deployed module uses its own Workload socket to do its communication with the runtime edgelet. This unpromptedly leads us to two bugs where where /mnt directory is not created properly upon startup on Windows.

Issues:
The two known bugs were:

1. EdgeAgent would have a hard time binding the socket i.e.

<3> 2021-08-31 00:04:34.253 +00:00 [ERR] - Executing command for operation ["create"] failed.
Microsoft.Azure.Devices.Edge.Agent.Edgelet.EdgeletCommunicationException- Message:Error calling Create module edgeHub: Could not create module edgeHub
caused by: Could not create module edgeHub
caused by: invalid volume specification: 'C:\ProgramData\iotedge\mnt\edgeHub:C:\ProgramData\iotedge\workload': invalid mount config for type "bind": bind source path does not exist: c:\programdata\iotedge\mnt\edgehub, StatusCode:500

This was fixed in 382cf77

2. IoTEdge runtime would have an issue starting up with "forbidden access" after Update-IoTEdge from a version prior to 1.1.5.

<0> 2021-09-04 14:45:48.824 +08:00 [FTL] - Fatal error building application.
System.Net.Internals.SocketExceptionFactory+ExtendedSocketException (10013): An attempt was made to access a socket in a way forbidden by its access permissions. C:\ProgramData\iotedge\workload\sock
   at System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress)
   at System.Net.Sockets.Socket.Connect(EndPoint remoteEP)

Fixes: #5465.

[arsing]

Perhaps update the PR description to include what Damon put in your previous one.