Fix#7453 Add option to omit failed values from Data Validator log messages

[leehaut]

Fix #7453

Summary

• Add a Data Validator option "Do not log failed validation data" (suppress_log_failed_data, default false) that omits failed field/row values from validation error messages (shown as ?), while still logging errors and routing rejected rows to error handling.
• Fix Data Validator dialog: after removing a validation rule, select and display the nearest remaining rule instead of leaving the editor blank.
• Add unit tests for validation rules, suppress-failed-data behavior, meta serialization/clone, and dialog selection index logic.
• Introduce BaseTransform.isLoggingErrorDescriptions() so transforms can optionally control whether putError writes error descriptions to the log.