## Description
[As of `httpx==0.23.1`](encode/httpx#2241), the `URL.raw` property was removed, which broke our `_url_to_str()` helper that uses that property to construct the raw URL.

However, the removed property was simply a combination of already existing (and still existing) properties in the `URL` object, which we can use to manually consturct the raw URL. I've version gated it such that nothing's changed for previous versions of `httpx`, but moving forward we'll manually construct the raw URL.

## Checklist
- [x] Add additional sections for `feat` and `fix` pull requests.
- [x] [Library documentation](https://github.com/DataDog/dd-trace-py/tree/1.x/docs) and/or [Datadog's documentation site](https://github.com/DataDog/documentation/) is updated. Link to doc PR in description.

## Motivation

## Design

## Testing strategy

## Relevant issue(s)

## Testing strategy

## Reviewer Checklist
- [ ] Title is accurate.
- [ ] Description motivates each change.
- [ ] No unnecessary changes were introduced in this PR.
- [ ] Avoid breaking [API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces) changes unless absolutely necessary.
- [ ] Tests provided or description of manual testing performed is included in the code or PR.
- [ ] Release note has been added for fixes and features, or else `changelog/no-changelog` label added.
- [ ] All relevant GitHub issues are correctly linked.
- [ ] Backports are identified and tagged with Mergifyio.

(cherry picked from commit 6a1948d)