replace some entity shortcut by fqdn

* ChillPerson:Person
* ChillMain:Center
* ChillActivity:Activity

src/Bundle/ChillMainBundle/Tests/Controller/UserControllerTest.php

@@ -161,7 +161,7 @@ final class UserControllerTest extends WebTestCase
 
         $user = self::$kernel->getContainer()
             ->get('doctrine.orm.entity_manager')
-            ->getRepository('ChillMainBundle:User')
+            ->getRepository(\Chill\MainBundle\Entity\User::class)
             ->findOneBy(['username' => $username]);
 
         $this->assertTrue($passwordEncoder->isPasswordValid($user, $password));

src/Bundle/ChillMainBundle/Tests/Export/ExportManagerTest.php

@@ -672,7 +672,7 @@ final class ExportManagerTest extends KernelTestCase
         $localUser = $user ?? self::$container->get(
             'doctrine.orm.entity_manager'
         )
-            ->getRepository('ChillMainBundle:User')
+            ->getRepository(\Chill\MainBundle\Entity\User::class)
             ->findOneBy(['username' => 'center a_social']);
         $token = new UsernamePasswordToken($localUser, 'password', 'provider');
         $tokenStorage = new TokenStorage();