Trace id confused with traceparent from http context in ProblemDetails Extensions?

## Summary

from httpContext trace identifier - we actually get trace parent which is of [this](https://github.com/w3c/trace-context/blob/main/spec/20-http_request_header_format.md) format:

```
version
trace-id
parent-id
trace-flags
```

I wanted to know why are we using traceId name instead of trace-parent while adding this value to problemDetails.Extensions [here:](https://github.com/dotnet/aspnetcore/blob/main/src/Mvc/Mvc.Core/src/Infrastructure/DefaultProblemDetailsFactory.cs)

Am I understanding it wrong?? should the
traceId be renamed to traceParent?