Bug: Trying to enumerate the result of DisplayArea.FindAll() throws an InvalidCastException

Description

With AOT on, call Microsoft.UI.Windowing.DisplayArea.FindAll().ToList() or anything else that tries to call GetEnumerator on the result of DisplayArea.FindAll() and it fails with an InvalidCastException. The stack trace is

[System.InvalidCastException user-unhandled]	
>	WinRT.Runtime.dll!WinRT.IObjectReference.As<WinRT.Interop.IUnknownVftbl>(System.Guid iid) Line 139	C#
 	WinRT.Runtime.dll!System.Collections.Generic.IReadOnlyListImpl<Microsoft.UI.Windowing.DisplayArea>.Make_IEnumerableObjRef() Line 47	C#
 	WinRT.Runtime.dll!System.Collections.Generic.IReadOnlyListImpl<Microsoft.UI.Windowing.DisplayArea>.iEnumerableObjRef.get() Line 25	C#
 	WinRT.Runtime.dll!System.Collections.Generic.IReadOnlyListImpl<Microsoft.UI.Windowing.DisplayArea>.GetEnumerator() Line 75	C#

Note that I wouldn't say this was a duplicate of https://github.com/microsoft/CsWinRT/issues/747 as previously suggested in this issue https://github.com/microsoft/microsoft-ui-xaml/issues/6454 since no covariance is involved here. Also, this is not the System.ArgumentOutOfRangeException mentioned in that issue. The workaround of using an integer indexer as in https://github.com/microsoft/microsoft-ui-xaml/issues/6454#issuecomment-2188377618 works.

Steps To Reproduce

See description

Expected Behavior

No exception

Version Info

CsWinRT 2.2, WindowsAppSdk.WinUI 1.8.260204000 (+ transitive dependencies), Windows 25H2.

Additional Context

No response

Start by reproducing the AOT failure with Microsoft.UI.Windowing.DisplayArea.FindAll().ToList() and inspect the WinRT.Runtime stack entries for IReadOnlyListImpl<Microsoft.UI.Windowing.DisplayArea>, Make_IEnumerableObjRef(), and GetEnumerator(). Done means enumeration succeeds without InvalidCastException while the existing integer-indexer workaround remains unnecessary.