Missing 'MicrosoftWindowsServer:WindowsServer:Windows-Server-Technical' platform image?

[windows-server-containers-preview](https://github.com/Azure/azure-quickstart-templates/tree/master/windows-server-containers-preview)

### Issue Details

When creating a deployment with the 'windows-server-containers-preview' template, I see this message in the error log

`"properties": {
"statusCode": "NotFound",
"serviceRequestId": "99d51643-512b-4bef-8d4d-60d194751e57",
"statusMessage": "{\"error\":{\"code\":\"ImageNotFound\",
\"target\":\"imageReference\",\"message\":
\"The platform image 'MicrosoftWindowsServer:WindowsServer:Windows-Server-Technical Preview:latest'
is not available. Verify that all fields in the storage profile are correct.\"}}"
},`

### Repro steps (*if necessary, delete otherwise*)
1. Configure the basic template parameters and run the deployment.

Start with the windows-server-containers-preview template linked in the issue and inspect its imageReference values. Reproduce the deployment using the basic parameters, verify which Microsoft Windows Server image is currently available, and consider the issue done when the template deploys without ImageNotFound.

Written by the indexing model from the issue text.