[BUG] Snackbar position on Modal Page is incorrect

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Did you read the "Reporting a bug" section on Contributing file?

- [x] I have read the "Reporting a bug" section on Contributing file: https://github.com/CommunityToolkit/Maui/blob/main/CONTRIBUTING.md#reporting-a-bug

### Current Behavior

When showing snackbar in a modal page, it is positioned higher. Referring to the 2 screenshots below, take note of the snackbar position in respect to the navigation bar.

(from MainPage)

(from Modal Page)

I've tried `this.DisplaySnackbar()` and `Snackbar.Make().Show()`. Both yield the same result.

### Expected Behavior

The snackbar position in the modal page should be the same as the main page.

### Steps To Reproduce

1. Open and run from the reproduction project repository
2. Click on the [Show Snackbar] button and take note of the snackbar position
3. Click on [PushModal] button to open up a modal page
4. Click on the [Show Snackbar] button and take note of the snackbar position in the modal page

### Link to public reproduction project repository

https://github.com/simon10says/SnackbarPosition

### Environment

```markdown
- .NET MAUI CommunityToolkit: 13.0.0
- OS: Android 15
- .NET MAUI: 10.0.11
```

### Anything else?

This is my 1st time using this, so I'm not sure if it works previously.