Fix comparison of document versions v0.1 and v0.1+

Users can no longer compare the working version of a document (v0.1+) with v0.1.

Steps to reproduce:

• As Admin, create a document.
• As a regular user with ReadWrite permission on the above document, edit the document's description.
• Click on Compare document action.
  => Toaster notification appears:

  There are no other versions to compare with.

Expected behavior:

• Working version (v0.1+) and v0.1 of the document's metadata should appear side by side for comparison.