Unit test bug: For testing strict mode new invalid test data generators are needed

[viktorvan]

This is a bug in the unit tests.

Describe the bug
The test generators for invalid data (pins and coord nums) are returning 12-digit strings. For the StrictMode.TenDigits we need 10-digit strings to test with, otherwise there is a small chance that the test will (incorrectly) fail. This will happen when the test number is for a person with age > 100.

What area is it related to
PersonalIdentityNumber, CoordinationNumber

To Reproduce
Run test pin with invalid day returns parsing error from PersonalIdentityNumber_ParseStrict.fs with replay seed: (98302403, 296865625).