Drupal module to delete the contents of a field

There is no module to do this. You could delete the field and recreate it, but you would have to

So core has the functionality but no direct mechanism to use it.

See also:

Make deleted fields work with config synch [#2198429] | Drupal.org

https://drupal.stackexchange.com/questions/177156/how-to-properly-delete-fields-programmatically