The uploaded file name in an interface

That is just a matter of how that full name is displayed. And no, this overflow behaviour cannot be adjusted.

You can access the file names and properties of the file in the context of the file upload validation using fv!file , as Stefan mentioned the name can not be extracted until form is submitted and access via the document object.

This is standard behavior of the File Upload Field.  It doesn't affect the name of the final uploaded file (which should remain the same as the original file's name unless you override it using controls within the component).