### 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)

editor_list.push_back(ep);
					}
				}
				if (!editor_list.is_empty()) {
					
					_open_editor_pressed();
					opened_editor = true;
				}
				_update_property_bg();
			}
			if (res.ptr() != sub_inspector->get_edited_object()) {
				sub_inspector->edit(res.ptr());
			}
		} else {
			if (sub_inspector) {
				set_bottom_editor(nullptr);
				memdelete(sub_inspector_vbox);
				sub_inspector = nullptr;
				sub_inspector_vbox = nullptr;
				if (opened_editor) {
					EditorNode::get_singleton()->hide_unused_editors();
					opened_editor = false;
				}
				_update_property_bg();
			}
		}
	}
	resource_picker->set_edited_resource(res);
}
void EditorPropertyResource::collapse_all_folding() {