FIX: Fixed a memory leak in OnScreenStick (#2006)

Author: ekcoh

Packages/com.unity.inputsystem/CHANGELOG.md

@@ -12,6 +12,7 @@ however, it has to be formatted properly to pass verification tests.
 
 ### Fixed
 - Fixed Multiple interactions could breaks on Composite Binding. [ISXB-619](https://issuetracker.unity3d.com/product/unity/issues/guid/ISXB-619)
+- Fixed memory leak when the OnScreenStick component was destroyed [ISXB-1070](https://issuetracker.unity3d.com/product/unity/issues/guid/ISXB-1070). Contribution by [LukeUnityDev](https://github.com/LukeUnityDev).
 
 ### Changed
 - Renamed editor Resources directories to PackageResources to fix package validation warnings.

Packages/com.unity.inputsystem/InputSystem/Plugins/OnScreen/OnScreenStick.cs

@@ -136,6 +136,15 @@ private void Start()
             image.alphaHitTestMinimumThreshold = 0.5f;
         }
 
+        private void OnDestroy()
+        {
+            if (m_UseIsolatedInputActions)
+            {
+                m_PointerDownAction.started -= OnPointerDown;
+                m_PointerDownAction.canceled -= OnPointerUp;
+            }
+        }
+
         private void BeginInteraction(Vector2 pointerPosition, Camera uiCamera)
         {
             var canvasRectTransform = UGUIOnScreenControlUtils.GetCanvasRectTransform(transform);