Data export doesnt work on Safari

The issue takes place when export files are stored to the private location. Hook "hook_file_download()" allows add headers to private files. Patch below adds the hook to the module. Also with this change JSON download also works in Safari.

I'm not sure what encoding is needed for filename inside of "Content-disposition" header, in Chrome and Safari it works with backslashes, URL encode and plane, even if filename has quotes. So I keep it plain, same to implementation in the module in DataExport::buildStandard()

I have this problem but I'm not using the private file system (only public), so the patch doesn't help me. I tried the event subscriber in #3, and while it did work, it seems a little overbearing to run that if statement on every page request across the site on the off chance that the request contains "csv". Adding to .htaccess as suggested in #2 didn't work for me.

In the end I did what was suggested by the reporter: Set the file name in the views path settings.

This is a bug for sure, but at least it's easily worked around.

I created a merge request based on @dewalt's patch and committed with them as the author of the commit.