Refactor norm method to accept Iterable instead of List

Author: Avaneeshakrishna

src/test/java/com/thealgorithms/backtracking/CombinationSumTest.java

@@ -8,8 +8,8 @@
 import org.junit.jupiter.api.Test;
 
 class CombinationSumTest {
-
-    private static List<List<Integer>> norm(List<List<Integer>> x) {
+    
+    private static List<List<Integer>> norm(Iterable<List<Integer>> x) {
         List<List<Integer>> y = new ArrayList<>();
         for (var p : x) {
             var q = new ArrayList<>(p);