eInvoicing: Set default send method to 'Not Registered'

The "Not Registered" function in version 2024.4 is designed for situations where customers are not registered with a TIN (Tax Identification Number).

When the Default Send Method is set to "Not Registered" for a customer (e.g., 3000/xxx), the details in the Action Button may still display "LHDNM."

This occurs because "LHDNM" is the default placeholder for adding a TIN.

If no TIN is provided, the system leaves the field blank and considers the customer as not registered. The send method, visually displaying "LHDNM," does not impact the actual functionality for non-registered customers.