Commit missing compile fix from cherry-pick conflict

oauth2/oauth2-client/src/test/java/org/springframework/security/oauth2/client/web/server/WebSessionOAuth2ServerAuthorizationRequestRepositoryTests.java

@@ -29,7 +29,7 @@ import org.springframework.security.oauth2.core.endpoint.OAuth2ParameterNames;
 import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.server.WebSession;
 
-import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
 /**
  * @author Rob Winch