Internal function to verify that, if there are `beautier` temporary files created, these are also cleaned up, as by CRAN policy.
check_empty_beautier_folder(beautier_folder = get_beautier_folder())
the path to the beautier temporary files folder
If the `beautier` folder does not exist, this function does nothing. If there are folder and/or files in the `beautier` folder, an error is given.
use remove_beautier_folder to remove the default `beautier` folder