[BUG] Incorrect shadow rendering on older Android versions for Popup v2

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Did you read the "Reporting a bug" section on Contributing file?

- [x] I have read the "Reporting a bug" section on Contributing file: https://github.com/CommunityToolkit/Maui/blob/main/CONTRIBUTING.md#reporting-a-bug

### Current Behavior

Popup v2 added a shadow which looks nice on a newer Android devices but it's not rendered correctly on older Android devices. I didn't investigate which versions work and which doesn't. For example an Android 16 and Android 12 Samsung devices work, but an older Android 7 device by Huawei doesn't - only a solid black box is drawn instead of a smooth shadow. The issue is more visible in the light mode but can be observed on some devices in the dark mode, too.

I didn't modified the Popup settings. The Community Toolkit default values are used.

The problem is both in the latest .NET 9 version and .NET 10 vesions of MAUI and the Toolkit.

| Android 12 and 16 (correct) | Android 7 (wrong) |
| ------------------------------ | --------------------- |
| | |

### Expected Behavior

The same behavior on all platforms and Android versions.

### Steps To Reproduce

1. Open and run the solution from the reproduction project on Android 7 emulator
2. Tap the "Open a popup" button
3. Check that the shadow is not smooth.
4. Try the same with, for example, Android 15 emulator (also in the light mode) and compare the difference how the shadow is displayed.

### Link to public reproduction project repository

https://github.com/holecekp/MauiBugPopupShadow

### Environment

```markdown
- .NET MAUI CommunityToolkit: 12.3, 13.0
- OS: Android 7 (both emulator and physical device)
- .NET MAUI: 9.0.120, 10.0.11
```

### Anything else?

_No response_