ItemsRepeater leak

[Mozart-UA]

Issue Description:

It seems that the ItemsRepeater component is causing memory leaks. After some investigation, I have determined that the leaks are due to lingering references to EventHandler in the OnLayoutChanged method.

Desktop/Platform:

• OS: Windows (10 / 11)
• FluentAvalonia Version (2.1.0 / 2.2.0)
• Avalonia Version 11.2.3

Steps to Reproduce:

1. Create a UserControl.
2. Place an empty ItemsRepeater on it, data binding is not necessary.
3. Create a window and display this UserControl in the new window as content.
4. Close the window.

LeakTestItemsRepeater.zip

Expected Behavior:
Closing the window should release all references to objects and remove the window from memory.

Actual Behavior:
References to the Window are held by the UserControl, references to the UserControl are held by ItemsRepeater, and references to ItemsRepeater are held by Layout. This causes memory leaks and prevents garbage collection. The specific event handlers involved are:

• Layout.MeasureInvalidated -/+ InvalidateMeasureForLayout;
• Layout.ArrangeInvalidated -/+ InvalidateArrangeForLayout;

Additional context:
See attached sample project. Each time the "Yes Leak" button is pressed, objects will be created, but will never be deleted from memory.
In contrast, clicking the "No Leak" button creates objects, and closing the window marks objects for deletion.