Provide an error message when a file is declared for writing that already exists.
check_file_exists(file, overwrite, call = caller_env())An error message saying the requested file already exists
The file that is being checked
Whether the file was declared to be overwritten
The calling environment to use in the error message
In the case of write_redcap_xlsx(), this should only error when a file
already exists and is not declared for overwite.