Remove public modifier on JUnit5 lifecycle methods

See gh-17292

spring-boot-samples/spring-boot-sample-property-validation/src/test/java/sample/propertyvalidation/SamplePropertyValidationApplicationTests.java

@@ -38,7 +38,7 @@ class SamplePropertyValidationApplicationTests {
 	private final AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
 
 	@AfterEach
-	public void closeContext() {
+	void closeContext() {
 		this.context.close();
 	}