Acrylic and Mica backdrops do not visually update when only TintOpacity changes

### Describe the bug

When you change the TintOpacity using the `DesktopAcrylicController` or using the `MicaController` the backdrop doesn't actually visually update until you also change any other property on the controller, example of this is shown in the attached video

https://github.com/user-attachments/assets/7162cf47-c8f2-4ee1-b0a5-fda008ba2e8b

### Steps to reproduce the bug

You need to create and apply the Acrylic/Mica controller, override the default TintColor, and then try chaning the TintOpacity, example of this can be found in [this repo](https://github.com/Gami13/GamiAutoClicker)

### Expected behavior

The backdrop should instantly update when TintOpacity is changed like it happens with other properties

### Screenshots

_No response_

### NuGet package version

WinUI 3 - Windows App SDK 1.7.3: 1.7.250606001

### Windows version

Windows 11 (24H2): Build 26100

### Additional context

_No response_

Start by reproducing the issue with the linked GamiAutoClicker example on Windows 11 using Windows App SDK 1.7.3, focusing on DesktopAcrylicController and MicaController when only TintOpacity changes. Trace the TintOpacity update path and verify that the backdrop visibly updates immediately without changing another property.

Written by the indexing model from the issue text.