refactor: remove code smell java:S5786 (#2159)

https://sonarcloud.io/organizations/iluwatar/rules?open=java%3AS5786&rule_key=java%3AS5786

model-view-controller/src/test/java/com/iluwatar/model/view/controller/GiantControllerTest.java

@@ -36,7 +36,7 @@ import org.junit.jupiter.api.Test;
  *
  * @author Jeroen Meulemeester
  */
-public class GiantControllerTest {
+class GiantControllerTest {
 
   /**
    * Verify if the controller passes the health level through to the model and vice versa

model-view-controller/src/test/java/com/iluwatar/model/view/controller/GiantModelTest.java

@@ -33,7 +33,7 @@ import org.junit.jupiter.api.Test;
  *
  * @author Jeroen Meulemeester
  */
-public class GiantModelTest {
+class GiantModelTest {
 
   /**
    * Verify if the health value is set properly though the constructor and setter

model-view-controller/src/test/java/com/iluwatar/model/view/controller/GiantViewTest.java

@@ -42,17 +42,17 @@ import org.slf4j.LoggerFactory;
  *
  * @author Jeroen Meulemeester
  */
-public class GiantViewTest {
+class GiantViewTest {
 
   private InMemoryAppender appender;
 
   @BeforeEach
-  public void setUp() {
+  void setUp() {
     appender = new InMemoryAppender(GiantView.class);
   }
 
   @AfterEach
-  public void tearDown() {
+  void tearDown() {
     appender.stop();
   }