DateTime in the data model cases crash on wrong input

### Description of the bug

When setting the date manually to a date that would not be possible like "32.13.2026" the validation step cases the app to crash out.

### Steps To Reproduce

1. Go to an app with a Datepicker, have the dataModel binding be a DateTime type.
2. Write a fake date that would not work
3. Click outside to blur the field

### Additional Information

_No response_

Start with the Datepicker's DateTime dataModel binding and reproduce the crash by entering "32.13.2026" before blurring the field. Trace the validation path for impossible dates and add or update coverage for this input. Done means invalid manual dates are handled as validation errors without crashing the app.

Written by the indexing model from the issue text.