Text colour does not update when changing system theme in Extension Settings

tl;dr: the text of adaptive cards doesn't hot-reload in response to a RequestedTheme change.

It should.

It's even more impossible to read when changing from Dark => light

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### Microsoft PowerToys version

0.100.0

### Installation method

Microsoft Store

### Area(s) with issue?

Command Palette

### Steps to reproduce

1. Open CmdPal Settings
2. Navigate to the Extensions page and click on an extension
3. Change the system theme

### ✔️ Expected Behavior

The text in the Extension settings updates

### ❌ Actual Behavior

The text colour remains the way it was before

https://github.com/user-attachments/assets/f06bd8b7-1da3-4d8b-be6f-64545b54ce06A

### Upload Bug Report ZIP-file

_No response_

### Additional Information

_No response_

### Other Software

_No response_

Reproduce the issue from CmdPal Settings by opening an extension and changing the system theme, then trace the Extension Settings adaptive cards and their RequestedTheme handling. Done means the text colour updates immediately in both dark-to-light and light-to-dark changes.

Written by the indexing model from the issue text.