hard to view the top right icons when Mica is enabled

### Windows Terminal version

1.17.11391

### Windows build number

10.0.22621.1778

### Other Software

_No response_

### Steps to reproduce

Create a custom theme and enable Mica:
```
{
"name": "Mica",
"tab":
{
"background": null,
"showCloseButton": "always",
"unfocusedBackground": null
},
"tabRow":
{
"background": "#00000000",
"unfocusedBackground": null
},
"window":
{
"applicationTheme": "system",
"useMica": true
}
}
```

### Expected Behavior

_No response_

### Actual Behavior


Start by reproducing the issue in Windows Terminal 1.17.11391 on Windows 10.0.22621.1778 with the supplied custom theme and Mica enabled, then inspect the rendering of the top-right icons. Done means the icons are clearly visible while retaining the configured Mica appearance; the issue names no files or tests to run.

Written by the indexing model from the issue text.