### 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)

GDCLASS(EditorPropertyClassName, EditorProperty);
private:
	CreateDialog *dialog = nullptr;
	Button *property = nullptr;
	String selected_type;
	String base_type;
	void _property_selected();
	void _dialog_created();
protected:
	virtual void _set_read_only(bool p_read_only) override;
	static void _bind_methods();
public:
	void setup(const String &p_base_type, const String &p_selected_type);
	virtual void update_property() override;
	EditorPropertyClassName();
};
class EditorPropertyCheck : public EditorProperty {