[MacCatalyst] Setting NULL for the DatePicker then the picker should default to Todays date when it's opened

[Dhivya-SF4094]

Description

On MacCatalyst, when the Date value is set to null and the date picker is opened, the picker defaults to 1/1/1900. The expected behavior is for it to default to today’s date instead.

After the changes in PR #30657, this behavior works as expected on iOS. However, on MacCatalyst, today’s date is still maintained, and the value is not set to null.

Before PR-30657	After PR-30657
Before_PR30657.mov	After_PR30657.mov

Steps to Reproduce

1. Run the attached sample DatePickerRepo.zip.
2. Click button to set NULL to DatePicker.
3. See Date is not cleared and still today's date is visible.

Link to public reproduction project repository

No response

Version with bug

10.0.0-preview.4

Is this a regression from previous behavior?

No, this is something new

Last version that worked well

No response

Affected platforms

macOS

Affected platform versions

No response

Did you find any workaround?

No response

Relevant log output

This issue has been verified in Visual Studio Code 1.103.0 with MAUI versions (10.0.0-preview.6.25359 & 10.0.0-preview.4.25263.4). It can be reproduced on the MacCatalyst platform.

Note: The nullable support for DatePicker was introduced in MAUI Version 10.0.0-preview.4.25263.4. (Reference: https://github.com/dotnet/maui/releases/tag/10.0.0-preview.4.25263.4)