[Port][2021.3][RG Viewer] Make sure the RG events are not unsubscribe…

…d when comming back from a Maximized state

The `OnDisable` is called just after the on Enable when coming back from a Maximized state. Making events unsubscribed.

Packages/com.unity.render-pipelines.core/Editor/RenderGraph/RenderGraphViewer.cs

@@ -676,11 +676,7 @@ void OnEnable()
         foreach (var graph in registeredGraph)
             m_RegisteredGraphs.Add(graph, new HashSet<string>());
 
-        RenderGraph.requireDebugData = true;
-        RenderGraph.onGraphRegistered += OnGraphRegistered;
-        RenderGraph.onGraphUnregistered += OnGraphUnregistered;
-        RenderGraph.onExecutionRegistered += OnExecutionRegistered;
-        RenderGraph.onExecutionUnregistered += OnExecutionUnregistered;
+        SubscribeToRenderGraphEvents();
     }
 
     private void CreateGUI()
@@ -690,10 +686,36 @@ private void CreateGUI()
 
     void OnDisable()
     {
+        UnsubscribeToRenderGraphEvents();
+    }
+
+    void SubscribeToRenderGraphEvents()
+    {
+        if (RenderGraph.requireDebugData)
+            return;
+
+        RenderGraph.requireDebugData = true;
+        RenderGraph.onGraphRegistered += OnGraphRegistered;
+        RenderGraph.onGraphUnregistered += OnGraphUnregistered;
+        RenderGraph.onExecutionRegistered += OnExecutionRegistered;
+        RenderGraph.onExecutionUnregistered += OnExecutionUnregistered;
+    }
+
+    void UnsubscribeToRenderGraphEvents()
+    {
+        if (!RenderGraph.requireDebugData)
+            return;
+
         RenderGraph.requireDebugData = false;
         RenderGraph.onGraphRegistered -= OnGraphRegistered;
         RenderGraph.onGraphUnregistered -= OnGraphUnregistered;
         RenderGraph.onExecutionRegistered -= OnExecutionRegistered;
         RenderGraph.onExecutionUnregistered -= OnExecutionUnregistered;
     }
+
+    void Update()
+    {
+        // UUM-70378: In case the OnDisable Unsubscribes to Render Graph events when coming back from a Maximized state
+        SubscribeToRenderGraphEvents();
+    }
 }