minor #10412 Remove useless use statements (FabienPapet)

This PR was submitted for the master branch but it was merged into the 4.1 branch instead (closes #10412).

Discussion
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Remove useless use statements

While browsing the documentation, I found out that these 2 statements where not used.

Commits
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98c22b3 Remove useless use statements

Author: javiereguiluz

security/impersonating_user.rst

@@ -93,8 +93,6 @@ In some cases you may need to get the object that represents the impersonator
 user rather than the impersonated user. Use the following snippet to iterate
 over the user's roles until you find one that is a ``SwitchUserRole`` object::
 
-    use Symfony\Component\Security\Core\Authentication\Token\Storage\TokenStorageInterface;
-    use Symfony\Component\Security\Core\Authorization\AuthorizationCheckerInterface;
     use Symfony\Component\Security\Core\Role\SwitchUserRole;
     use Symfony\Component\Security\Core\Security;
     // ...