Default rendition should be "Default rendition" and not "None"

Steps to reproduce:

• Navigate to a document.
• Click on the Publish document document action.
  => Internal Publication dialog opens.
  => The rendition that is already selected under the Renditions field (the first one in the list) is "None".
  => You have to click on the dropdown menu in order to select "Default rendition".

By definition, the default rendition should be "Default rendition"