fix(util): use using statement for JAction in Reset_AllowsReuse test (#611)

Fixes CodeQL alert cs/dispose-not-called-on-throw. If Execute(),
Reset(), or Do() threw an exception, Dispose() would not be called.

Using a using declaration ensures the JAction is disposed even if
an exception occurs.

Signed-off-by: JasonXuDeveloper - 傑 <jason@xgamedev.net>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Author: JasonXuDeveloper

UnityProject/Packages/com.jasonxudeveloper.jengine.util/Tests/Editor/JActionTests.cs

@@ -473,7 +473,7 @@ public void Reset_AllowsReuse()
         {
             int counter = 0;
 
-            var action = JAction.Create()
+            using var action = JAction.Create()
                 .Do(() => counter++);
 
             action.Execute();
@@ -484,8 +484,6 @@ public void Reset_AllowsReuse()
                 .Execute();
 
             Assert.AreEqual(11, counter);
-
-            action.Dispose();
         }
 
         #endregion