[MDS-5737] Fixed incosistent path on new file uploads

[simensma-fresh]

Objective

MDS-5737

The new file upload logic didn't append the S3_PREFIX when saving the object_store_path, just when copying the file there, making the saved path referencing a file that doesn't exist.

A couple of other changes:

• Leftover fix for Viewing documents in document viewer when using the action menu in Minespace
• Updated filesystem_manager env variable to match what's expected. Syncfusion should now work out of the box when running the project locally as long as the filesystem_provider pod is running