Fix checkstyle

Author: mhalbritter

module/spring-boot-webtestclient/src/test/java/org/springframework/boot/webflux/test/autoconfigure/WebTestClientAutoConfigurationTests.java

@@ -87,13 +87,11 @@ void shouldFailWhenDefaultWebHandlerIsNotAvailable() {
 	void shouldFailWithNeitherDefaultWebHandlerNorWebApplicationContext() {
 		ClassLoader parentClassLoader = Thread.currentThread().getContextClassLoader();
 		this.contextRunner.withClassLoader(new FilteredClassLoader(parentClassLoader, WebApplicationContext.class))
-			.run((context) -> {
-				assertThat(context).getFailure()
-					.rootCause()
-					.isInstanceOf(RuntimeException.class)
-					.hasMessageStartingWith("Mock WebTestClient support requires")
-					.hasMessageContaining("WebApplicationContext");
-			});
+			.run((context) -> assertThat(context).getFailure()
+				.rootCause()
+				.isInstanceOf(RuntimeException.class)
+				.hasMessageStartingWith("Mock WebTestClient support requires")
+				.hasMessageContaining("WebApplicationContext"));
 	}
 
 	@Test