Merge branch...

Merge branch '6667-bug-in-mail_mail_domain_plugin-function-mail_mail_domain_edit-spamfilter-update-iterate-over' into 'develop'

Resolve "Bug in mail_mail_domain_plugin function mail_mail_domain_edit spamfilter update iterate over column insteat rows"

Closes #6667

See merge request ispconfig/ispconfig3!1866