[iOS] Collectionview itemslayout styling changes with footer

[Uridel]

Description

When using a collectionview that has the itemslayout property and a footer the styling becomes all wrong.
So far I have only encountered this on iOS and when there is 1 item in the collection.

Code to reproduce:

`

<ContentPage.Resources>
</ContentPage.Resources>

<CollectionView x:Name="collection" ItemsLayout="VerticalGrid, 2">
	<CollectionView.ItemTemplate>
		<DataTemplate>
			<Label Text="{Binding Name}" BackgroundColor="red" HeightRequest="200" HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand"/>
		</DataTemplate>
	</CollectionView.ItemTemplate>
	<CollectionView.Footer>
		<ContentView >
			<ContentView.ControlTemplate>
				<ControlTemplate>
					<Grid RowDefinitions="Auto, *">
						<ContentPresenter Grid.Row="0"/>
						<ContentView Grid.Row="1"  HeightRequest="100" InputTransparent="True"/>
					</Grid>
				</ControlTemplate>
			</ContentView.ControlTemplate>
		</ContentView>
	</CollectionView.Footer>
</CollectionView>

`

Steps to Reproduce

1. Create a collectionview with 1 item and add ItemsLayout="VerticalGrid, 2"
2. Add a Footer with a contentview controltemplate
3. have it contain any 2 controls
4. The item will be displayed in the middle instead of to the left.

Expected behavior
The item is shown on the left side of the page

Actual behavior
The item is shown on the middle of the page

Link to public reproduction project repository

https://github.com/Uridel/CollectionviewLayout

Version with bug

8.0.14 SR3.1

Is this a regression from previous behavior?

Yes, this used to work in Xamarin.Forms

Last version that worked well

Unknown/Other

Affected platforms

iOS

Affected platform versions

No response

Did you find any workaround?

no

Relevant log output

No response

[Uridel]

Here is a link to the project with which it can be reproduced https://github.com/Uridel/CollectionviewLayout

[QianaJiao]

Can repro this issue at iOS platform on the latest 17.10 Preview 6 (8.0.3 & 8.0.21).