[Windows] Shadow Size Not Updating Properly at Runtime

### Description

When a shadow is applied to a .NET MAUI view on Windows, changing the view’s height or width at runtime causes the shadow size to update slowly. This results in a visible blinking or flickering effect around the view's shadow during resizing.

### Steps to Reproduce

1. Run the attached sample
2. Click the button to change width and height
3. you can see shadow size updating slowly (blinking) after view size updated.

### Link to public reproduction project repository

[ShadowIssue.zip](https://github.com/user-attachments/files/20666419/ShadowIssue.zip)

https://github.com/user-attachments/assets/7cd8f116-497e-4739-9608-432b0836d50d

### Version with bug

9.0.70 SR7

### Is this a regression from previous behavior?

No, this is something new

### Last version that worked well

Unknown/Other

### Affected platforms

Windows

### Affected platform versions

_No response_

### Did you find any workaround?

No

### Relevant log output

```shell

```

The payload provides ShadowIssue.zip as the reproduction project; start by running it on Windows and reproducing a resize after clicking the button. Trace the Windows shadow update path, then verify that changing width and height no longer produces delayed shadow resizing or visible flicker.

Written by the indexing model from the issue text.