Drop-down options in Settings always follow system theme

### Windows Terminal version

1.18.1421.0

### Windows build number

10.0.22621.1702

### Other Software

_No response_

### Steps to reproduce

1. set the WT theme to be the opposite of your system theme. In my case, system theme is light but Terminal is set to dark.
2. open Settings
3. click any option that has a drop-down.

### Expected Behavior

The application theme is followed, in my case dark.

### Actual Behavior

The system theme is followed, in my case light
(on the right is the Settings app showing that my system theme is light.)

Reproduce the issue by setting the Windows Terminal theme opposite to the system theme, opening Settings, and checking a drop-down option. Start by tracing how the Settings UI applies its theme; done means drop-down controls follow the application theme rather than the system theme.

Written by the indexing model from the issue text.