### Godot version

4.0-rc6

### System information

Fedora 37, Mesa Intel ADL GT2

### Issue description

Code that works as expected at runtime fails with Nil references to (assigned) exported vars in the editor:

![tool_global_position_error](https://user-images.githubusercontent.com/364501/222031460-ffb1ecbd-5175-4a42-8470-25285ba5f821.png)


### Steps to reproduce

Try to access the `global_position` of a `Node3D` that's assigned to an exported var.

See that it works at runtime.

See that it errors in the editor with:

> Invalid get index 'global_position' (on base: 'Nil').

### Minimal reproduction project

[tool_test.zip](https://github.com/godotengine/godot/files/10856640/tool_test.zip)

class EditorSpinSlider;
class PropertySelector;
class SceneTreeDialog;
class TextEdit;
class TextureButton;
class EditorPropertyNil : public EditorProperty {
	GDCLASS(EditorPropertyNil, EditorProperty);
	LineEdit *text = nullptr;
public:
	virtual void update_property() override;
	EditorPropertyNil();
};
class EditorPropertyText : public EditorProperty {
	GDCLASS(EditorPropertyText, EditorProperty);
	LineEdit *text = nullptr;
	bool updating = false;
	bool string_name = false;
	void _text_changed(const String &p_string);
	void _text_submitted(const String &p_string);
protected:
	virtual void _set_read_only(bool p_read_only) override;
	static void _bind_methods();
public:
	void set_string_name(bool p_enabled);
	virtual void update_property() override;
	void set_placeholder(const String &p_string);
	void set_secret(bool p_enabled);
	EditorPropertyText();
};
class EditorPropertyMultilineText : public EditorProperty {