Removed superfluous service validation logic

[TavoNiievez]

TL;DR: The validation that the service exists was already done when obtaining the service. The code that is removed in this PR was not necessary.

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$this->grabService() validates that the service exists and otherwise fails the test showing a very descriptive message.

module-symfony/src/Codeception/Module/Symfony.php

Lines 597 to 606 in b65b2c7

	public function grabService(string $service)
	{
	$container = $this->_getContainer();
	if (!$container->has($service)) {
	$this->fail("Service $service is not available in container.
	If the service isn't injected anywhere in your app, you need to set it to `public` in your `config/services_test.php`/`.yaml`,
	see https://symfony.com/doc/current/testing.html#accessing-the-container");
	}
	return $container->get($service);
	}

I had ignored that this implicit validation already existed when writing the functions that i edit in this PR:

logout, seeInSession, amOnAction, seeAuthentication, seeUserHasRole, dontSeeAuthentication, grabParameter, seeCurrentActionIs, seeUserPasswordDoesNotNeedRehash, amLoggedInAs.