*Reproducibe on:*
* VS version: 1.7.3
* Unity version: 2021.2.0b7
* Platform: Windows 10

*Steps to Reproduce:*
# Create a game object, add a script machine with a script graph
# Create a simple debug logic on the graph
# Enter play mode

*Actual Results:*
* Null texture warning spamming in the console

{code:java}
null texture passed to GUI.DrawTexture UnityEngine.GUI:DrawTexture (UnityEngine.Rect,UnityEngine.Texture) Unity.VisualScripting.LudiqGUI:OnHeaderIconGUI (Unity.VisualScripting.EditorTexture,UnityEngine.Rect) (at Packages/com.unity.visualscripting/Editor/VisualScripting.Core/Interface/LudiqGUI.cs:958) Unity.VisualScripting.LudiqGUI:OnHeaderGUI (Unity.VisualScripting.LudiqGUI/GetHeaderTitleHeightDelegate,Unity.VisualScripting.LudiqGUI/GetHeaderSummaryHeightDelegate,Unity.VisualScripting.LudiqGUI/OnHeaderTitleGUIDelegate,Unity.VisualScripting.LudiqGUI/OnHeaderSummaryGUIDelegate,Unity.VisualScripting.EditorTexture,UnityEngine.Rect,single&,bool,single) (at Packages/com.unity.visualscripting/Editor/VisualScripting.Core/Interface/LudiqGUI.cs:902) Unity.VisualScripting.LudiqGUI:OnHeaderGUI (Unity.VisualScripting.Metadata,Unity.VisualScripting.Metadata,Unity.VisualScripting.EditorTexture,UnityEngine.Rect,single&,bool) (at Packages/com.unity.visualscripting/Editor/VisualScripting.Core/Interface/LudiqGUI.cs:1044) Unity.VisualScripting.GraphEditor:OnHeaderGUI (UnityEngine.Rect) (at Packages/com.unity.visualscripting/Editor/VisualScripting.Core/Inspection/GraphEditor.cs:42) Unity.VisualScripting.FlowGraphEditor:OnGUI (UnityEngine.Rect,UnityEngine.GUIContent) (at Packages/com.unity.visualscripting/Editor/VisualScripting.Flow/FlowGraphEditor.cs:59) Unity.VisualScripting.Inspector:Draw (UnityEngine.Rect,UnityEngine.GUIContent) (at Packages/com.unity.visualscripting/Editor/VisualScripting.Core/Inspection/Inspector.cs:134) Unity.VisualScripting.LudiqGUI:Editor (Unity.VisualScripting.Metadata,UnityEngine.Rect) (at Packages/com.unity.visualscripting/Editor/VisualScripting.Core/Interface/LudiqGUI.cs:102) Unity.VisualScripting.GraphInspectorPanel:OnGUI (UnityEngine.Rect) (at Packages/com.unity.visualscripting/Editor/VisualScripting.Core/Windows/GraphInspectorPanel.cs:39) Unity.VisualScripting.SidebarPanel:OnGUI (UnityEngine.Rect,single&,System.Nullable1) (at Packages/com.unity.visualscripting/Editor/VisualScripting.Core/Windows/Sidebars/SidebarPanel.cs:151)
Unity.VisualScripting.Sidebar:OnGUI (UnityEngine.Rect) (at Packages/com.unity.visualscripting/Editor/VisualScripting.Core/Windows/Sidebars/Sidebar.cs:149)
Unity.VisualScripting.Sidebar:DrawLayout () (at Packages/com.unity.visualscripting/Editor/VisualScripting.Core/Windows/Sidebars/Sidebar.cs:55)
Unity.VisualScripting.GraphWindow:OnGUI () (at Packages/com.unity.visualscripting/Editor/VisualScripting.Core/Windows/GraphWindow.cs:592)
UnityEngine.GUIUtility:ProcessEvent (int,intptr,bool&)`{code}

*Expected Results:*
* No warnings should appear in the console.