clean_header breaks HTTPS check of WordPress

clean_header() removes some headers that are essential for the HTTPS check of WordPress and people see “Talk to your web host about resolving this HTTPS issue for your website.” in the healt check (internally “It looks like the response did not come from this site.” is returned as error description).

See https://github.com/WordPress/WordPress/blame/e1239d91a95177506d1e3cc0a6ed8ed3232130f6/wp-includes/https-detection.php#L204-L227

Also removing these headers brings no advantages regarding SEO or security. This is just Security by Obscurity (removing such information does not prevent attacks, anyone can easily guess and check, that it is WordPress).