[12.x] Option to disable dispatchAfterResponse in a test

[gdebrauwer]

When you use afterResponse() on a job in route and you want to test that job, then there is currently no easy way to do this because the job will never be executed in the test.

/** @test */
public function some_job()
{
    dispatch(function () {
         // will not be executed when running the test
    })->afterResponse();
}

This PR fixes that by providing an option to disable (similar to withoutDefer)

/** @test */
public function some_job()
{
    Bus::disableDispatchingAfterResponse();

    dispatch(function () {
         // will be executed when running the test
    })->afterResponse();
}