Remove bind_dn_template from jupyter ldap authenticator default

[PACordonnier]

When using jupyter hub installs, tdp_vars_default ldapauthenticator for jupyter contains the key bind_dn_templates

https://github.com/TOSIT-IO/tdp-collection-extras/blob/4199630a36a1268c4bc38b6a48a8ae6b326dc8c2/tdp_vars_defaults/jupyter/jupyter.yml#L72C1-L72C51

In my config, this should not be defined, hence with the merge behaviour of the variables this is still defined and cause authentication issue. I need this config to not defined