Revisit how we handle duplicate TRNs in TRS

[mason-emily]

Why?

There are sometimes cases where teachers have duplicate records in DQT with different TRNs. These cases are resolved by TRA by deactivating and merging records. We don't think this is an issue for participant registration in ECF2 as the DQT API gives an error when the deactivated TRN is used.

However we need to consider what happens in ECF when a TRN gets deactivated after an ECT or mentor is already registered. We also need to understand how this will work in future TRS.

What?

• Consider how we can help users resolve issues when they try to use a deactivated TRN
• Consider how we handle deactivated TRNs after registration

Helpful links or other information

https://ukgovernmentdfe.slack.com/archives/C06V31R0Z17/p1727077583727699

List of DQT errors: https://github.com/DFE-Digital/teaching-record-system/blob/0a2ff998022e04434053dabf5fc4bc0ca40b019e/TeachingRecordSystem/src/TeachingRecordSystem.Api/Validation/ErrorRegistry.cs#L5

[kas-madrigal]

@mason-emily we did some work on this as well!