hide_label() has no effect for fields in media library

[HPiirainen]

When registering fields for attachments, hide_label() has no effect. The resulting CSS for hiding the label is

div.acf-field.acf-field-{field-key} > div.acf-label > label { display: none; }

but the media library meta fields use table markup. div.acf-label could be changed to .acf-label to target all elements.