[13.x] Add Client\Request::uri()

[stevebauman]

Description:

This PR adds uri() method to Illuminate\Http\Client\Request to return an Illuminate\Support\Uri instance, matching the method available on Illuminate\Http\Request.

Example:

Http::fake();

Http::get('https://example.com/api/users?page=2');

Http::assertSent(function (Request $request) {
    return $request->uri()->path() === '/api/users'
        && $request->uri()->query()->integer('page') === 2;
});