fix checkstyle issue

Author: polyzos

fluss-client/src/test/java/com/alibaba/fluss/client/utils/ConverterUtilsTest.java

@@ -47,6 +47,7 @@
 import java.util.Objects;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
 /** Tests for {@link ConverterUtils}. */
 public class ConverterUtilsTest extends ClientToServerITCaseBase {
@@ -191,10 +192,8 @@ public void testPartialPojo() {
                         .build();
 
         // Expect an IllegalArgumentException when creating a converter with a field not in the POJO
-        assertThat(
-                        org.junit.jupiter.api.Assertions.assertThrows(
-                                IllegalArgumentException.class,
-                                () -> ConverterUtils.getConverter(PartialTestPojo.class, rowType)))
+        assertThatThrownBy(() -> ConverterUtils.getConverter(PartialTestPojo.class, rowType))
+                .isInstanceOf(IllegalArgumentException.class)
                 .hasMessageContaining("Field 'extraField' not found in POJO class");
     }