Fix Delete Headers for AssignmentRecord / PersonRecord / PositionRecord

[alexrudall]

As far as we can tell there are 3 types of records which require a start and end date to uniquely identify them, and the ID alone is not enough:

• Assignment Record
• PersonRecord
• PositionRecord

Deletion rows appear as ASD, PRD, POD respectively. In practice it looks like these deletion rows only contain the ID of the records, e.g.

ASD~123456

If we receive that row, should we delete ALL AssignmentRecords containing that ID, even if there are multiple records of that type (with different dates)?

• Find example of ASD / PRD / POD row
• Waiting to hear back from NHS ESR team for clarification
• Update codebase to handle them, if they include start and end dates