Introduce new `non_existing_record_id`/`non_existing_record_iid` spec helpers and fix id dependent specs

What does this MR do?

This introduces new non_existing_record_id/non_existing_record_iid spec helpers to avoid using 123/999 for "non-existing ID/IIDs" in specs.

Does this MR meet the acceptance criteria?

Conformity

• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Separation of EE specific content