Change guzzle client creation (linked to PR in laravel-plugin)

[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/laravel-plugin/pull/62 make that possible with minimal changes.