TextBlock in Checked ToggleButton is illegible

### Description

When using the light or dark fluent theme, a TextBlock in a checked ToggleButton is very hard to read as the foreground doesn't change. If you use plain text it does work as expected.

### Reproduction Steps

```

Foo


Foo

```

### Expected behavior

Both buttons look the same. For my particular settings that means blue background, white foreground.

### Actual behavior

Both buttons look different. For my particular settings that means:
* Top button: blue background / black foreground -> hard to read
* Bottom button: blue background / white foreground

### Regression?

The top button isn't hard to read in Aero2.

### Known Workarounds

_No response_

### Impact

_No response_

### Configuration

.NET 10
Windows 11

### Other information

_No response_