add UnitTest about MessageConvert

infra/common/src/main/java/cn/hippo4j/common/toolkit/MessageConvert.java

@@ -31,6 +31,10 @@ import lombok.SneakyThrows;
  */
 public class MessageConvert {
 
+    private MessageConvert(){
+
+    }
+
     /**
      * {@link Message} to {@link MessageWrapper}.
      *

infra/common/src/test/java/cn/hippo4j/common/toolkit/MessageConvertTest.java

@@ -33,12 +33,6 @@ import java.util.*;
  */
 public class MessageConvertTest {
 
-    @Test
-    public void TestMessageConvert(){
-        MessageConvert messageConvert = new MessageConvert();
-        Assertions.assertNotNull(messageConvert);
-    }
-
     @Test
     public void testConvert() {
         AbstractMessage message = new RuntimeMessage();