Aspera: many Nuxeo documents are created for an uploaded file

During the devs on NXP-27574 and when adding a new test to test the whole integration from creating a transfer with uploaded files until the creation of the Nuxeo documents related to the upload files. We observed that for a given Aspera Files, the Aspera Worker create three different documents for the same file 2 versions + 1 ordinary doc.

The documents are created: 

•  Using Operation: Here It seems that we call an operation to create a Nuxeo document related to the upload file but we find ourselves with the needed document and a version
• Save Doc: It seems that here we have also a new version.

After discussion with PO it seems that there is a bug. we don't need to have three documents. Also note that the second creation here causes a random failure here and the error on org.nuxeo.ecm.core.api.ConcurrentUpdateException: Concurrent update

The idea of this this ticket is to ensure that we have one and only one document for given Aspera uploaded file.

From a quick investigation it seems that the second creation here is responsible of the CI failure. To be able to build the preview and as we are going to rework this part of worker to be replaced by a computation see NXP-29311
we will Ignore the test which is randomly fails 

fyi We saw the issue of the three created documents when adding the new test Here we use a txt file. For images/audios on local deployment it's not reproducible but it was for txt file. Which it means the issue is related to TEXT/PLAIN mime type.