minor #32001 [Security] Fix AuthenticationException::getToken typehint (norkunas)

This PR was merged into the 3.4 branch.

Discussion
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[Security] Fix AuthenticationException::getToken typehint

| Q             | A
| ------------- | ---
| Branch?       | 3.4 <!-- see below -->
| Bug fix?      | no
| New feature?  | no <!-- please update src/**/CHANGELOG.md files -->
| BC breaks?    | no     <!-- see https://symfony.com/bc -->
| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Tests pass?   | yes    <!-- please add some, will be required by reviewers -->
| Fixed tickets | #...   <!-- #-prefixed issue number(s), if any -->
| License       | MIT
| Doc PR        | symfony/symfony-docs#... <!-- required for new features -->

The token may be not set when throwing AuthenticationException.

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Commits
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a9705a0143 Fix AuthenticationException::getToken typehint

Author: Robin Chalas

Exception/AuthenticationException.php

@@ -26,7 +26,7 @@ class AuthenticationException extends \RuntimeException implements \Serializable
     /**
      * Get the token.
      *
-     * @return TokenInterface
+     * @return TokenInterface|null
      */
     public function getToken()
     {