[Bug] Shell.SearchHandler shows items with full screen height on Android

[mkanyo]

Description

Running the latest version of Xamarin Forms 5.0.0.1874 the Shell.SearchHandler shows search result items with full screen height on Android.

Steps to Reproduce

The issue can currently be observed by running the Xamarin Form Sample Xaminals.

This is the repo:
https://github.com/xamarin/xamarin-forms-samples/tree/master/UserInterface/Xaminals

In the MoneysPage.xaml
The SearchHandler is defined like this:

    <Shell.SearchHandler>
        <controls:MonkeySearchHandler Placeholder="Enter search term"
                                      ShowsResults="true"
                                      DisplayMemberName="Name" />
    </Shell.SearchHandler>

The custom SearchHandler is like so:

using System.Linq;
using System.Threading.Tasks;
using Xamarin.Forms;
using Xaminals.Data;
using Xaminals.Models;

namespace Xaminals.Controls
{
    public class MonkeySearchHandler : SearchHandler
    {
        protected override void OnQueryChanged(string oldValue, string newValue)
        {
            base.OnQueryChanged(oldValue, newValue);

            if (string.IsNullOrWhiteSpace(newValue))
            {
                ItemsSource = null;
            }
            else
            {
                ItemsSource = MonkeyData.Monkeys
                    .Where(monkey => monkey.Name.ToLower().Contains(newValue.ToLower()))
                    .ToList<Animal>();
            }
        }

        protected override async void OnItemSelected(object item)
        {
            base.OnItemSelected(item);
            await Task.Delay(1000);

            // Note: strings will be URL encoded for navigation (e.g. "Blue Monkey" becomes "Blue%20Monkey"). Therefore, decode at the receiver.
            // This works because route names are unique in this application.
            await Shell.Current.GoToAsync($"monkeydetails?name={((Animal)item).Name}");
            // The full route is shown below.
            // await Shell.Current.GoToAsync($"//animals/monkeys/monkeydetails?name={((Animal)item).Name}");
        }
    }
}

Expected Behavior

The search items should render under each other with reasonable size.

Actual Behavior

Each item gets full screen height and the list therefore becomes huge with full screen items and a lengthy scrollbar.

Basic Information

• Version with issue: 5.0.0.1874
• Last known good version: 5.0.0.1791-pre5
• Platform Target Frameworks:
  • Android: 10.0,

Screenshots

Screenshot:
https://www.screencast.com/users/MiklosKanyo/folders/Default/media/83b3ee95-98ae-49ec-9933-57853968e787

Video:
https://www.screencast.com/users/MiklosKanyo/folders/Default/media/5adeb4e5-45d4-42e4-a13b-86cc1e510442

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Microsoft Visual Studio Professional 2019
Version 16.8.3
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Reproduction Link

https://github.com/xamarin/xamarin-forms-samples/tree/master/UserInterface/Xaminals

Workaround

Rolling back to version 5.0.0.1791-pre5