[12.x] Unset global middleware deactivation when running withoutMiddleware with filled parameters

[noefleury]

Currently when we run consecutive tests in the same test-case (eg: few calls to do E2E testing), there is a situation which make withoutMiddleware usage discussable.

$this->withoutMiddleware()->post('/uri');
// some assertions
$this->withoutMiddleware(MyAuthMiddleware::class)->get('/uri/{resource}');

The second call to withoutMiddleware() will currently don't change nothing as the first call set the instance middleware.disable to true.

What is your opinion on the fact to unset it if we call withoutMiddleware with given parameters ?

This PR should not impact current usages.