### 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)

#include "editor_properties.h"
#include "core/config/project_settings.h"
#include "core/core_string_names.h"
#include "editor/create_dialog.h"
#include "editor/editor_node.h"
#include "editor/editor_properties_array_dict.h"
#include "editor/editor_properties_vector.h"
#include "editor/editor_resource_picker.h"
#include "editor/editor_scale.h"
#include "editor/editor_settings.h"
#include "editor/gui/editor_file_dialog.h"
#include "editor/gui/editor_spin_slider.h"
#include "editor/gui/scene_tree_editor.h"
#include "editor/inspector_dock.h"
#include "editor/plugins/script_editor_plugin.h"
#include "editor/project_settings_editor.h"
#include "editor/property_selector.h"
#include "scene/2d/gpu_particles_2d.h"
#include "scene/3d/fog_volume.h"
#include "scene/3d/gpu_particles_3d.h"
#include "scene/gui/color_picker.h"
#include "scene/main/window.h"
#include "scene/resources/font.h"
#include "scene/resources/mesh.h"
#include "scene/resources/packed_scene.h"
void EditorPropertyNil::update_property() {