[5.5] Ensure user is logged before expecting user instance type.

[shulard]

When using the assertAuthenticatedAs method, if the user is not logged, the output message was strange. This PR introduce a new check to ensure the user is logged.

Before :

Tests\Feature\RegisterControllerTest::testRegisterWithSpecificRole with data set #3 (5)
The currently authenticated user is not who was expected
Failed asserting that Act\User Object (...) is an instance of class "Illuminate\Foundation\Testing\TestCase".

After :

Tests\Feature\RegisterControllerTest::testRegisterWithSpecificRole with data set #3 (5)
The current user is not authenticated.

[shulard]

The behaviour is the same on the 5.4 branch in the seeIsAuthenticatedAs method, I can make a PR on previous branches too.