Accessibility bug: Windows App SDK 1.6 breaks NVDA's mouse tracking in WinUI.

### Describe the bug

I'm not sure if it's appropriate to report this bug here, but it seems to be related only to the version of the SDK.

Win UI apps using Windows App SDK 1.6 cannot be accessed using NVDA's mouse tracking.

### Steps to reproduce the bug

1. Download and run NVDA (using a temporary copy should be sufficient.)
2. Open Settings via the notification icon and enable the following options:
* Vision: Enable Highlighting
* Mouse: Enable mouse tracking
* Review Cursor: Follow mouse cursor
3. Use the mouse to view WinUI apps for different Windows App SDK versions

### Expected behavior

Report what is under the mouse.

### Screenshots


Microsoft.WindowsAppSDK Version="1.6.240923002"


Microsoft.WindowsAppSDK Version="1.5.241107002"

### NuGet package version

Windows App SDK 1.6.2: 1.6.241106002

### Packaging type

Packaged (MSIX)

### Windows version

Windows 11 version 22H2 (22621, 2022 Update)

### IDE

Visual Studio 2022

### Additional context

_No response_

Reproduce the problem with NVDA's mouse tracking using a packaged WinUI app and compare Windows App SDK 1.6.2 with 1.5. Confirm whether the regression is specific to the 1.6 SDK and whether the mouse reports the content under the pointer as expected. The issue names no source file or test entry point, so further investigation will need to locate the affected accessibility path.

Written by the indexing model from the issue text.