[CarouselViewHandler2] CurrentItem Not Updating with Vertical LinearItemsLayout

### Description

- In CarouselViewHandler2, when using LinearItemsLayout with Orientation="Vertical", the CurrentItem property does not update correctly, whereas it works as expected in CarouselViewHandler1.

| CarouselViewHandler1 | CarouselViewHandler2 |
|----------|----------|
| | |

### Steps to Reproduce

1. Download the attached sample project.
2. Run the application and scroll the CarouselView vertically.
3. Observe that the CurrentItem property does not update as the items change.

[SampleRepo.zip](https://github.com/user-attachments/files/23047767/SampleRepo.zip)

### Link to public reproduction project repository

_No response_

### Version with bug

9.0.120

### Is this a regression from previous behavior?

No, this is something new

### Last version that worked well

_No response_

### Affected platforms

iOS

### Affected platform versions

_No response_

### Did you find any workaround?

_No response_

### Relevant log output

```shell

```