[BUG]: Glitchy background behavior on power display popup opening

### Microsoft PowerToys version

0.99.0

### Installation method

PowerToys auto-update

### Area(s) with issue?

Power Display

### Steps to reproduce

1- Open the popup and see a glitch on open

https://github.com/user-attachments/assets/7ff8b50c-1548-4e19-98f8-bcf3697f9cdd

### ✔️ Expected Behavior

No glitch of the background on open

### ❌ Actual Behavior

Background visual grlitches (black then non transprent then mica background instead of mica directly)

### Upload Bug Report ZIP-file

_No response_

### Additional Information

_No response_

### Other Software

_No response_

Start by reproducing the glitch in the Power Display popup described in the issue and inspect the popup's opening path. Compare the observed black, non-transparent, and Mica transition with the expected direct Mica background. Done means the popup opens without any visible background transition glitch.

Written by the indexing model from the issue text.