Make IShape in MauiCALayer a WeakReference

[MarcelStommel]

Description of Change

Fixes a memory leak in MauiCALayer by making it's IShape? _shape field a weak reference, as proposed in the attached Issue.
The leak happens from the fact that most IShapes are also Views and thereby have access to the UI's NameScope and x:Nameed elements, which causes a ref-count cycle.

Issues Fixed

Fixes #26169
App to reproduce the memory leak / Test the fix: https://github.com/MarcelStommel/LayerLeak

[dotnet-policy-service]

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

[jsuarezruiz]

/azp run

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[jsuarezruiz]

We have some specific tests to verify that controls not leaks here

maui/src/Controls/tests/DeviceTests/Memory/MemoryTests.cs

Line 162 in 90e36c5

[InlineData(typeof(RoundRectangle))]

But, not cover the scenario from https://github.com/MarcelStommel/LayerLeak/

Could you include a new test?

maui/src/Core/tests/UnitTests/Views/ShapeTests.cs

Line 11 in 90e36c5

public class ShapeTests

[MarcelStommel]

Added the Device Test as part of BorderTests, since that's also how I did it in https://github.com/MarcelStommel/LayerLeak/

(Sorry about the other GitHub account, I just had to test it on my private MacBook and that was just the easiest way to get the changes pushed.)
@dotnet-policy-service agree company="Quality Bytes GmbH"

[rmarinho]

/azp run

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Azure Pipelines successfully started running 3 pipeline(s).