[IcDatePicker] - changing startOfWeek prop from initial value has no effect

[ad9242]

Summary of the bug

If changing the startOfWeek prop from an initial value, it has no effect on the display of the picker

🪜 How to reproduce

With the following stackblitz example

1. Open the date picker
2. See that Sunday is the start of the week in the picker Click on the Button to change the startOfWeek
3. Open the date picker & see that sunday is stil the first day of the week - it's should now be friday

🧐 Expected behaviour

The first day of the week in the picker should reflect the new value set

📝 Acceptance Criteria

Given a datepicker has an initial startOfWeek prop value set When changing the prop to a new value Then the start of week should change in the picker