minor #33864 Replace deprecated calls in tests (jakzal)

This PR was merged into the 4.3 branch.

Discussion
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Replace deprecated calls in tests

| Q             | A
| ------------- | ---
| Branch?       | 4.3
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Tickets       | -
| License       | MIT
| Doc PR        | -

Commits
-------

5aee2f140b Replace deprecated calls in tests

src/Symfony/Component/Security/Http/Tests/Firewall/SwitchUserListenerTest.php

@@ -231,7 +231,7 @@ class SwitchUserListenerTest extends TestCase
             ->method('checkPostAuth')->with($user);
 
         $listener = new SwitchUserListener($this->tokenStorage, $this->userProvider, $this->userChecker, 'provider123', $this->accessDecisionManager);
-        $listener->handle($this->event);
+        $listener($this->event);
 
         $this->assertSame([], $this->request->query->all());
         $this->assertSame('', $this->request->server->get('QUERY_STRING'));