Clean up import statements in StochasticMatrixTest

Removed unused import statements for cleaner code.

Author: Dsannue

src/test/java/com/thealgorithms/matrix/StochasticMatrixTest.java

@@ -1,9 +1,7 @@
 package com.thealgorithms.matrix;
 
 import static org.junit.jupiter.api.Assertions.assertTrue;
-
 import static org.junit.jupiter.api.Assertions.assertFalse;
-
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;