[BUG] Registered template details are not returned by API

[marrobi]

Describe the bug
When register a template, such as azureml_devtestlabs using https://xxx.cloudapp.azure.com/api/workspace-templates and then retrieve with https:/xxx.cloudapp.azure.com/api/workspace-templates/tre-workspace-azureml_devtestlabs get:

{
  "errors": [
    "Workspace template does not exist"
  ]
}

Steps to reproduce

1. cd /workspaces/azureml_devtestlabs
2. ../../devops/scripts/publish_register_bundle.sh -u https://xxx.cloudapp.azure.com -r xxx -t workspace -i
3. curl -X 'GET' \ 'https://xxx.cloudapp.azure.com/api/workspace-templates/tre-workspace-azureml_devtestlabs' \ -H 'accept: application/json'

@TessFerrandez can you have a look at this. Thanks.