Problem details middleware ignores response status code when handling an exception.

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Describe the bug

I tried to use problem details middleware and exception handler middleware in this manner:

```
builder.Services.AddExceptionHandler();
builder.Services.AddProblemDetails(options =>
{
options.CustomizeProblemDetails = context =>
{
if (context.Exception is MyUserFacingException)
{
context.ProblemDetails.Details = context.Exception.Message;
}
};
});

app.UseStatusCodePages();
app.UseExceptionHandler();
```

If the exception handler returns true then `ProblemDetailsContext.Exception` is null. I think this makes sense since the handler returning true means the exception does not propagate. The problem details middleware initializes `ProblemDetailsContext.ProblemDetails` to whatever status code was set by the exception handling middleware.

If the exception handler returns false, then the exception is available in `ProblemDetailsContext.Exception`, which is good. But now the problem details middleware always initializes `ProblemDetailsContext.ProblemDetails` as a 500, ignoring the status code set by the exception handler middleware. And there's no way to leverage the existing defaults to re-initialize it (https://github.com/dotnet/aspnetcore/issues/47978). The actual HTTP response code is the one set by the exception handler, not the 500 shown in the problem details.

Searching the code base for uses of `ProblemDetailsDefaults.Apply`, the only place it's called with a null status code that would result in it defaulting to 500 is here:

https://github.com/dotnet/aspnetcore/blob/6b9bba1472da66a9f02ae3cd0f564ad6e2bb5fff/src/Http/Http.Results/src/ProblemHttpResult.cs#L24

### Expected Behavior

The problem details middleware should always initialize `ProblemDetailsContext.ProblemDetails` using `HttpContext.Response.StatusCode`.

### Steps To Reproduce

_No response_

### Exceptions (if any)

_No response_

### .NET Version

8.0.400

### Anything else?

_No response_