Fix JwtAuthenticationProvider Checkstyle

Issue gh-17251

Author: rwinch

oauth2/oauth2-resource-server/src/test/java/org/springframework/security/oauth2/server/resource/authentication/JwtAuthenticationProviderTests.java

@@ -35,7 +35,9 @@
 import org.springframework.security.oauth2.jwt.TestJwts;
 import org.springframework.security.oauth2.server.resource.BearerTokenErrorCodes;
 
-import static org.assertj.core.api.Assertions.*;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
 import static org.mockito.BDDMockito.given;
 import static org.mockito.Mockito.mock;