Remove deprecation linked to kernel shutdown

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

@@ -29,8 +29,6 @@ final class UserControllerTest extends WebTestCase
 
     protected function setUp(): void
     {
-        self::bootKernel();
-
         $this->client = self::createClient([], [
             'PHP_AUTH_USER' => 'admin',
             'PHP_AUTH_PW' => 'password',
@@ -49,6 +47,7 @@ final class UserControllerTest extends WebTestCase
         }
 
         $em->flush();
+        self::ensureKernelShutdown();
     }
 
     public function dataGenerateUserId()
@@ -69,6 +68,8 @@ final class UserControllerTest extends WebTestCase
         $this->toDelete[] = [User::class, $user->getId()];
 
         yield [$user->getId(), $user->getUsername()];
+
+        self::ensureKernelShutdown();
     }
 
     public function testList()