### 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)

case Variant::TRANSFORM3D: {
			EditorPropertyTransform3D *editor = memnew(EditorPropertyTransform3D);
			EditorPropertyRangeHint hint = _parse_range_hint(p_hint, p_hint_text, default_float_step);
			editor->setup(hint.min, hint.max, hint.step, hint.hide_slider, hint.suffix);
			return editor;
		} break;
		case Variant::PROJECTION: {
			EditorPropertyProjection *editor = memnew(EditorPropertyProjection);
			EditorPropertyRangeHint hint = _parse_range_hint(p_hint, p_hint_text, default_float_step);
			editor->setup(hint.min, hint.max, hint.step, hint.hide_slider, hint.suffix);
			return editor;
		} break;
		
		case Variant::COLOR: {
			EditorPropertyColor *editor = memnew(EditorPropertyColor);
			editor->setup(p_hint != PROPERTY_HINT_COLOR_NO_ALPHA);
			return editor;
		} break;
		case Variant::STRING_NAME: {
			if (p_hint == PROPERTY_HINT_ENUM || p_hint == PROPERTY_HINT_ENUM_SUGGESTION) {
				EditorPropertyTextEnum *editor = memnew(EditorPropertyTextEnum);
				Vector<String> options = p_hint_text.split(",", false);
				editor->setup(options, true, (p_hint == PROPERTY_HINT_ENUM_SUGGESTION));
				return editor;
			} else {
				EditorPropertyText *editor = memnew(EditorPropertyText);
				if (p_hint == PROPERTY_HINT_PLACEHOLDER_TEXT) {
					editor->set_placeholder(p_hint_text);
				} else if (p_hint == PROPERTY_HINT_PASSWORD) {
					editor->set_secret(true);