I had some user related ACF fields, I merged those fields to other fields. Now I want to get rid of old fields which have no use anymore. I assume that deleting these user related ACF fields from wp-admin ACF plugin menu won’t delete the meta_keys and meta_values from specific users which had data assigned to those fields? Am I right? Do I need to write wpdb queries to get rid of that fields? Does leaving such data can be dangerous?