Add guzzle sender that extends Saloon's default sender (linked to PR in saloon itself)

[gdebrauwer]

I noticed the laravel-http-sender package is being sunset, but I still want requests/responses to be logged in Telescope. Then I discovered this is possible with the following package: https://github.com/huzaifaarain/telescope-guzzle-watcher/tree/main

The problem is that this package only works if the guzzle client is created using the service container. That is currently not the case.

This PR and PR https://github.com/saloonphp/saloon/pull/403 make that possible with minimal changes.