Remove unused import

Issue gh-10277

acl/src/test/java/org/springframework/security/acls/domain/AclAuthorizationStrategyImplTests.java

@@ -18,7 +18,6 @@ package org.springframework.security.acls.domain;
 
 import java.util.Arrays;
 
-import org.assertj.core.api.Assertions;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;