Before this commit, the text of a `CopyClipboardButtonField` could be edited with a `label` option. But this label was never translated. After this commit, the field `string` is used instead to rename the button. This is automatically exported for translatation. task-3054813 closes odoo/odoo#105560 Signed-off-by: Antoine Vandevenne (anv) <anv@odoo.com>