PEPPOL-COMMON-R040: GLN must have a valid format according to GS1 rules

In UBL, for each of cbc:EndpointID, cac:PartyIdentification/cbc:ID, or cbc:CompanyID where the attribute schemeID equals '0088', the element's text value, after ignoring surrounding whitespace, must consist only of digits (0-9) and must pass the rule's GLN format function u:gln(). The value must not be empty or only whitespace, and it cannot contain non-digit characters. If the value is all digits but u:gln() returns false, the rule also fails; the function enforces the GS1 GLN format as referenced by the rule.

Set the value of the appropriate element (cbc:EndpointID, cac:PartyIdentification/cbc:ID, or cbc:CompanyID) with schemeID="0088" to a valid GLN that consists only of digits and passes the u:gln() check. Since the rule does not list the internal algorithm of u:gln(), verify the GLN against GS1 format requirements (typically including a correct check digit) as the validator expects. Replace or correct the current value without changing the schemeID.