fix: revert ReverseStack deletion and verify linting (#6474) (#6494)

* fix: revert ReverseStack deletions and ensure lint compliance

* Fix formatting for ReverseStack and test files

* Delete ReverseStackUsingRecursion and its test as requested

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>

src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java

@@ -38,6 +38,9 @@ public final class ReverseStack {
      * @param stack the stack to reverse; should not be null
      */
     public static void reverseStack(Stack<Integer> stack) {
+        if (stack == null) {
+            throw new IllegalArgumentException("Stack cannot be null");
+        }
         if (stack.isEmpty()) {
             return;
         }