Setting Opacity to ProfilePicture incorrectly displays initials behind the picture

### Describe the bug

The above one is when Opacity is set to 0.5, the other one is when Opacity is the default value, 1.0.

### Why is this important?

This issue is especially noticeable when it's used in TitleBar, which sets Opacity of Icon, Title, LeftHeader, RightHeader, etc. to 0.5.

See the "T" shown in the ProfilePicture in the screenshot, which shouldn't be the right visual.

### Steps to reproduce the bug

```xml

```

### Actual behavior

As aforementioned.

### Expected behavior

Initials should not be visible when the `ProfilePicture.ProfilePicture` prop is set

### Screenshots

### NuGet package version

2.4.0

### Windows version

Windows 11 (25H2): Build 26200

### Additional context

Here's the repro.
[App1.zip](https://github.com/user-attachments/files/32296403/App1.zip)

Start with the PersonPicture control and reproduce the issue using the supplied XAML snippet and App1.zip. Compare rendering with Opacity set to 0.5 and 1.0, then verify that initials are not visible when ProfilePicture is set and that the result matches the screenshots.

Written by the indexing model from the issue text.