Description

When importing people, if the organization for example uses swedish "personnummer" as a person's date-of-birth, it is not possible to import this as a date as the importer as it only wants dates that are of a specific shape.

Steps to reproduce

1. Start an import by going to orgs/1/people and selecting "import people" from the top right corner menu
2. Select a file that has a column containing swedish "personnummer"
3. Select to import this column as "Extra date"
4. Also select an ID so that you can click "Validate" at the bottom right corner

Expected Behaviour

Recieve no errors

Actual Behaviour

You get an error message that the values are of the wrong format and cannot be imported as dates.

Screenshots (if you have any)

Suggested solution

Use similar logic as in "gen 2" to do a special solution for the swedes.