Fix: ArgumentNullException: Parameter name: _unity_self

[ErnSur]

Repro:

• Select instance of Console Request so that inspector is drawing Exchange Editor
• reload assembly a couple of times

Clues:

• It seems to be connected to Inspector Element drawing an instance of Scriptable Object that is saved and loadded using InternalEditorUtility.SaveToSerializedFileAndForget.
• This exception doesn't seem to trigger when inspecting RequestConsoleDatabase which is also saved using InternalEditorUtility.SaveToSerializedFileAndForget
• ConsoleRequestData is different from RequestConsoleDatabase in a way that it has different hide flags

Exception:

ArgumentNullException: Value cannot be null.
Parameter name: _unity_self
UnityEditor.UIElements.InspectorElement.GetOrCreateEditor (UnityEditor.SerializedObject serializedObject) (at /Users/bokken/buildslave/unity/build/Editor/Mono/UIElements/Inspector/InspectorElement.cs:384)
UnityEditor.UIElements.InspectorElement.Reset (UnityEditor.SerializedObject bindObject) (at /Users/bokken/buildslave/unity/build/Editor/Mono/UIElements/Inspector/InspectorElement.cs:305)
UnityEditor.UIElements.InspectorElement.ExecuteDefaultActionAtTarget (UnityEngine.UIElements.EventBase evt) (at /Users/bokken/buildslave/unity/build/Editor/Mono/UIElements/Inspector/InspectorElement.cs:379)
UnityEngine.UIElements.CallbackEventHandler.HandleEvent (UnityEngine.UIElements.EventBase evt) (at /Users/bokken/buildslave/unity/build/ModuleOverrides/com.unity.ui/Core/Events/EventHandler.cs:281)
UnityEngine.UIElements.CallbackEventHandler.HandleEventAtCurrentTargetAndPhase (UnityEngine.UIElements.EventBase evt) (at /Users/bokken/buildslave/unity/build/ModuleOverrides/com.unity.ui/Core/Events/EventHandler.cs:189)
UnityEngine.UIElements.CallbackEventHandler.HandleEventAtTargetPhase (UnityEngine.UIElements.EventBase evt) (at /Users/bokken/buildslave/unity/build/ModuleOverrides/com.unity.ui/Core/Events/EventHandler.cs:175)
UnityEngine.UIElements.CallbackEventHandler.HandleEventAtTargetAndDefaultPhase (UnityEngine.UIElements.EventBase evt) (at /Users/bokken/buildslave/unity/build/ModuleOverrides/com.unity.ui/Core/Events/EventHandler.cs:180)
UnityEditor.UIElements.Bindings.SerializedObjectBindingContext.SendBindingEvent[TEventType] (TEventType evt, UnityEngine.UIElements.VisualElement target) (at /Users/bokken/buildslave/unity/build/ModuleOverrides/com.unity.ui/Editor/Bindings/BindingExtensions.cs:84)
UnityEditor.UIElements.Bindings.SerializedObjectBindingContext.BindTree (UnityEngine.UIElements.VisualElement element, UnityEditor.SerializedProperty parentProperty) (at /Users/bokken/buildslave/unity/build/ModuleOverrides/com.unity.ui/Editor/Bindings/BindingExtensions.cs:94)
UnityEditor.UIElements.Bindings.SerializedObjectBindingContext.ContinueBinding (UnityEngine.UIElements.VisualElement element, UnityEditor.SerializedProperty parentProperty) (at /Users/bokken/buildslave/unity/build/ModuleOverrides/com.unity.ui/Editor/Bindings/BindingExtensions.cs:39)
UnityEditor.UIElements.Bindings.DefaultSerializedObjectBindingImplementation+BindingRequest.Bind (UnityEngine.UIElements.VisualElement element) (at /Users/bokken/buildslave/unity/build/ModuleOverrides/com.unity.ui/Editor/Bindings/BindingExtensions.cs:1119)
UnityEngine.UIElements.VisualTreeBindingsUpdater.Update () (at /Users/bokken/buildslave/unity/build/ModuleOverrides/com.unity.ui/Core/Bindings/VisualTreeBindingsUpdater.cs:272)
UnityEngine.UIElements.VisualTreeUpdater.UpdateVisualTreePhase (UnityEngine.UIElements.VisualTreeUpdatePhase phase) (at /Users/bokken/buildslave/unity/build/ModuleOverrides/com.unity.ui/Core/VisualTreeUpdater.cs:111)
UnityEngine.UIElements.Panel.UpdateBindings () (at /Users/bokken/buildslave/unity/build/ModuleOverrides/com.unity.ui/Core/Panel.cs:973)
UnityEngine.UIElements.UIElementsUtility.UnityEngine.UIElements.IUIElementsUtility.UpdateSchedulers () (at /Users/bokken/buildslave/unity/build/ModuleOverrides/com.unity.ui/Core/UIElementsUtility.cs:255)
UnityEngine.UIElements.UIEventRegistration.UpdateSchedulers () (at /Users/bokken/buildslave/unity/build/ModuleOverrides/com.unity.ui/Core/UIElementsUtility.cs:105)
UnityEditor.RetainedMode.UpdateSchedulers () (at /Users/bokken/buildslave/unity/build/ModuleOverrides/com.unity.ui/Editor/RetainedMode.cs:55)