lang/php80: Fix "can't locate API module structure `php8_module' in file /usr/local/libexec/apache24/libphp.so"

Because of the SHORTMODNAME an entry for php8_module was added to httpd.conf when installing www/mod_php80.
This was an error, because the module is now simple named "php_module".

PR: 251411
Reported by: <freebsd-bugzilla@b-society.se>
Sponsored by: PHP Update Service