This commit improves the various sharing templates to check if there is a configured mail template before suggesting to share the course/slide by email. Currently the user gets an error message suggesting to configure templates, which is not ideal as the sharing feature can be used by everyone including portal users, that have no idea what that means. Task-3349606 closes odoo/odoo#123702 Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>