CollectionView2 Layout Misalignment in GridItemsLayout with Horizontal Orientation on iOS and Catalyst

### Description

When using CollectionView2 with a GridItemsLayout and Orientation="Horizontal", the layout is not properly arranged. The header text appears misaligned and stretched, while the items are not correctly arranged. However, when using CollectionView1, the layout renders correctly.

-Using CollectionView1

https://github.com/user-attachments/assets/284646c3-10bd-41e9-9333-739499037147

- Using CollectionView2

https://github.com/user-attachments/assets/a4659173-be9a-4b1d-9dd2-dbfd6e4de447

### Steps to Reproduce

1. Launch the HostApp on iOS and Catalyst https://github.com/dotnet/maui/blob/main/src/Controls/tests/TestCases.HostApp/Elements/CollectionView/HeaderFooterGalleries/HeaderFooterGridHorizontal.xaml
2. Use CollectionView2 with a GridItemsLayout (Span=3, Orientation=Horizontal).
3. Observe that the header, footer, and items are misaligned.

Expected Behavior:
The header, footer, and items should be arranged correctly, as seen in CollectionView1.

Actual Behavior:

- Header text is stretched and misaligned.

- Footer does not align correctly with the content.

### Link to public reproduction project repository

_No response_

### Version with bug

9.0.40 SR4

### Is this a regression from previous behavior?

Not sure, did not test other versions

### Last version that worked well

_No response_

### Affected platforms

iOS, macOS

### Affected platform versions

_No response_

### Did you find any workaround?

_No response_

### Relevant log output

```shell

```

Start with src/Controls/tests/TestCases.HostApp/Elements/CollectionView/HeaderFooterGalleries/HeaderFooterGridHorizontal.xaml and run the HostApp reproduction on iOS and Catalyst. Compare the CollectionView2 GridItemsLayout case with CollectionView1 using Span=3 and Horizontal orientation. Done means the header, footer, and items align correctly on both affected platforms.

Written by the indexing model from the issue text.