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/test/java/com/thealgorithms/datastructures/stacks/ReverseStackTest.java

@@ -1,6 +1,7 @@
 package com.thealgorithms.datastructures.stacks;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.util.Stack;
@@ -8,6 +9,11 @@ import org.junit.jupiter.api.Test;
 
 class ReverseStackTest {
 
+    @Test
+    void testReverseNullStack() {
+        assertThrows(IllegalArgumentException.class, () -> ReverseStack.reverseStack(null), "Reversing a null stack should throw an IllegalArgumentException.");
+    }
+
     @Test
     void testReverseEmptyStack() {
         Stack<Integer> stack = new Stack<>();