Make sure end-to-end test uses unique filename in metrics test
What does this MR do?
In the case an error occurs during the file creation process, but after the file is created, the retry of the example will now fail before creating the new file since a file already exists with the same name. This MR makes sure the file created has a unique name each time.
Closes #228597 (closed).
Edited by Rémy Coutable