[iOS] Simplify iOS ScrollView - improvement

[kubaflo]

Description of Change

I think, I've identified a potential regression related to the simplified ScrollView on iOS (#26763). The issue occurs when an explicit HeightRequest is set on the ScrollView. In such cases, the content of the ScrollView is restricted to the specified height, which prevents scrolling as intended.

Issues Fixed

Fixes #26900

<ScrollView HeightRequest="200" BackgroundColor="Blue">
        <VerticalStackLayout BackgroundColor="Yellow">
                <Label Text="Hello, world!"
                        HeightRequest="250"
                        BackgroundColor="Red"/>
                <Label Text="Hello, world2!"
                        BackgroundColor="Green"
                        HeightRequest="200"/>
        </VerticalStackLayout>
</ScrollView>

Before	After
Screen.Recording.2025-01-01.at.02.26.16.mov	Screen.Recording.2025-01-01.at.02.32.19.mov

[dotnet-policy-service]

Hey there @kubaflo! Thank you so much for your PR! Someone from the team will get assigned to your PR shortly and we'll get it reviewed.

[kubaflo]

@albyrock87 could you please take a look :)

[albyrock87]

@kubaflo good catch.. this use case was totally missing from UI tests.

If you could add a UI test which covers this it'd be great!

The fix itself looks good to me.

[kubaflo]

@albyrock87 sure! I will add a UI test soon

[kubaflo]

@albyrock87 I've just added a test :)

[jfversluis]

/azp run

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