Narrator does not read selected text in WPF TextBox

### Description

When text is selected in WPF TextBox, Narrator does not pronounce/read it. It does not read the text even if the `CapsLock+Shift+Down` key combination is used. The same functionality works correctly in WinForms.

### Reproduction Steps

1. Open the solution from the attached archive in Visual Studio ([narratorTest.zip](https://github.com/user-attachments/files/19860771/narratorTest.zip)).
2. Run the `WpfApp2` project.
3. Start Narrator.
4. Select different parts of the text in the TextBox element shown in the application's window.
5. Use the `CapsLock+Shift+Down` key combination.

(The [screencast_with_audio.mp4](https://github.com/user-attachments/assets/e3c471c2-9a32-46c0-ba9a-06da2e3a60a1) illustrates these steps and the problematic behavior.)

### Expected behavior

* When selection is changed, Narrator pronounces "\[SELECTED_TEXT_PART\] text is selected".
* When the `CapsLock+Shift+Down` key combination is used, Narrator reads the text from the selection.

### Actual behavior

Narrator keeps silent and does not read anything when selection is changed or when the `Caps+Shift+Down` key combination is used.

The `Caps+Shjift+Down+Down` key combination still works - narrator reads letters from the selection.

The [screencast_with_audio.mp4](https://github.com/user-attachments/assets/e3c471c2-9a32-46c0-ba9a-06da2e3a60a1) illustrates the problematic behavior.

### Important:

If you use the same steps in the WinFormsApp1 project included into the same solution, you can see that Narrator works as expected.

### Regression?

_No response_

### Known Workarounds

_No response_

### Impact

The behavior prevents implementing full support for accessibility in WPF applications and does not allow people to hear what they selected if they cannot see it.

### Configuration

.NET 9, Windows 11.

### Other information

_No response_