DictionaryKeyPropertyAttribute not working

### Description

Class define with `DictionaryKeyPropertyAttribute` still show `All objects added to an IDictionary must have a Key attribute or some other type of key associated with them.` error while building project.

### Reproduction Steps

Define a class with `DictionaryKeyPropertyAttribute`.
```
[DictionaryKeyProperty("TargetType")]
public class MyStyle
{
public MyStyle()
{

}

public Type TargetType { get; set; }
}
```
Use it in a xaml file.
```

```

### Expected behavior

Build successful

### Actual behavior

Build failed

### Regression?

_No response_

### Known Workarounds

_No response_

### Impact

_No response_

### Configuration

_No response_

### Other information

[WpfApp1.zip](https://github.com/dotnet/wpf/files/10802921/WpfApp1.zip)