fix checkstyle

Author: Samuel Facchinello

src/test/java/com/thealgorithms/maths/MatrixUtilTest.java

@@ -1,11 +1,11 @@
 package com.thealgorithms.maths;
 
-import static org.junit.jupiter.api.Assertions.*;
+import org.junit.jupiter.api.Test;
 
 import java.math.BigDecimal;
-import java.util.Arrays;
 import java.util.Objects;
-import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 class MatrixUtilTest {