minor #27349 [Security] Fix missing use in UserInterface (jvasseur)

This PR was merged into the 4.1 branch.

Discussion
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[Security] Fix missing use in UserInterface

| Q             | A
| ------------- | ---
| Branch?       | 4.1
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| License       | MIT

Fix missing `Role` use used in the `getRoles` return type.

Commits
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3e0a0f4cb5 Fix missing use in UserInterface

src/Symfony/Component/Security/Core/User/UserInterface.php

@@ -11,6 +11,8 @@
 
 namespace Symfony\Component\Security\Core\User;
 
+use Symfony\Component\Security\Core\Role\Role;
+
 /**
  * Represents the interface that all user classes must implement.
  *