Improve error message when gitlab_group_ldap_link.id is invalid

Heidi Berryrequested to merge
improve-ldap-error into main

This change improves error handling in a function that parses GitLab group LDAP link identifiers. Instead of using a generic error message, the code now uses a more informative error format that includes the actual problematic input value when the ID doesn't have the expected structure. This makes debugging easier by showing developers exactly what invalid input caused the error, rather than just saying something went wrong.

Related to #6682

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