fix regression in DatePicker: invert first and last dates (#4661)

Author: ndonkoHenri

sdk/python/packages/flet/src/flet/core/date_picker.py

@@ -92,8 +92,8 @@ def __init__(
         self,
         open: bool = False,
         value: Optional[DateTimeValue] = None,
-        first_date: DateTimeValue = datetime(year=2050, month=1, day=1),
-        last_date: DateTimeValue = datetime(year=1900, month=1, day=1),
+        first_date: DateTimeValue = datetime(year=1900, month=1, day=1),
+        last_date: DateTimeValue = datetime(year=2050, month=1, day=1),
         current_date: DateTimeValue = datetime.now(),
         keyboard_type: Optional[KeyboardType] = None,
         date_picker_mode: Optional[DatePickerMode] = None,